2GB RAM on Windows 8 or 10 is completely usable for common computing tasks. Web browsing is tricky, particularly with Chrome, which at this point is pretty disrespectful of machines with limited amounts of RAM. Firefox and IE both do better. Some of the desktops I support are 2GB Windows 8 machines. For the most part, they're all subjectively identical to 4GB and 8GB machines until enough tabs or PDFs are open for Windows to start swapping.

I have a "Type"-style (the same sort the Pro 3 uses) purple cover for my Pro 2. I paid $58 for it on Amazon. I actually wanted purple but I could've gotten a pink one even cheaper. Would I take a refurbished keyboard? No question that I would. We use other people's keyboards all the damned time, especially those of us who have an IT support component to our jobs (or for that matter anyone who has ever used an ATM). Am I looking places besides major retailers? No I am not. If you can't find one at a significant discount, you probably shouldn't be buying anything over the internet.

The Surface keyboard is entirely optional. I don't completely love the Windows on-screen keyboard, though it's a damned-sight better than the one Apple ships with iOS (Apple is either not a big fan of basic literacy or thinks letters should always be displayed in uppercase regardless of the state of the shift key). In practice I've found that I don't use it much because my Surface Pro more as a very capable mobile device than as something for real work, but I have powerful desktops and a good laptop available to me as well.

Speaking to the quality of Apple's input devices specifically, I find the lack of key travel and mildly idiosyncratic layout on Apple's own branded keyboards uncomfortable for serious typing in exactly the same way the Surface Type-style keyboard is. I also question the ergonomics of the palmrests on its notebooks and the insistence on comically oversized touchpads as input devices. I wouldn't exactly say either option is without compromise.

MSRP is $130 for a Surface Pro 3 keyboard. They generally sell for under $100, sometimes under $80 if you don't mind one of the less popular colors or getting a refurbished one. I'm not sure where you're getting this $200 figure from, but it's significantly off-base.
Further, the Surface Pro doesn't have a hard requirement that you use Microsoft's keyboard. You can use any bluetooth or USB input devices you'd like.

If the CPUs are very similar and the machines are "nearly half as fast", I strongly suspect you're comparing a system with an SSD to one without. There's nothing special or magical about Apple's OS or hardware that would otherwise account for that difference.

Anything that has a modern LSI chip can probably be flashed to Target Initiator mode. I've gotten PERC and IBM M-series SAS controllers for $80 off ebay. You can add in an SAS expander if you need more than 8 drives.
With that kind of setup, you don't have to depend on motherboard ports and can buy whatever makes the most sense.

Ordinarily, I'd agree with you, but a few weeks ago I saw Chrome hit just a little short of 9GB RAM utilization on a machine that had been rebooted perhaps four hours before, with only a dozen open tabs. Was that a poor interaction between Chrome and my ad blocker and whatever the hell javascript and .GIFVs on Imgur does? Probably. But there's no way a browser's processes should be using more RAM than running virtual machines.

Pick a benchmark that's representative of your computing needs. Look at relevant benchmark scores.

Recent Intel CPUs are differentiated by their GPUs and TDP moreso than clock speed or thread performance, which is probably why a brand new Haswell i3 is only just a bit faster than an original Nehalem i7 from all the way back in 2008.

If you want top-end per thread performance, you probably want an i5. If you want that and need more cores than a typical desktop, get an i7. You probably don't need to worry about anything else; even five year old desktop and laptop parts are going to be subjectively similar to new for anything but a narrow range of content creation, gaming or scientific applications (assuming similar amounts of RAM and disk subsystems, that is). Whatever CPU you buy will probably be good enough for the life of the other components in the computer.

It's certainly a hassle to compare between CPUs on differing device types (e.g. is a 15W ULV i7 faster than a four year old 45W mobile i3?) but the truth is that within broad categories, newer things are faster and the classifications hold up. If you're doing an apples to oranges comparison, you have to look at whatever benchmark you think might be most relevant.

There's a considerable difference in the bulk of a phone with an external battery pack and a replaceable battery. I'd definitely rather have one than the other.

The Galaxy S5 and LG G3 are probably the best fit options.

I carry an S4 and I seldom need to replace the battery, but a few times a year I go to events where I hundreds photos or videos over four or five hours. I probably wind up swapping the battery at least twice on those days. Even if the need is irregular, not having the ability would be a deal breaker for me, too.

Generally speaking, the CPU branding is an indicator of feature set and relative performance within a generation and product class. We have desktop, mobile and (ultra)low-voltage part. If you're getting hung up trying to determine which CPU is faster between two CPUs of wildly different architectures (desktop Sandy Bridge vs. low-voltage Broadwell, for example), it's almost always going to be an apples to oranges comparison anyway; you're probably looking at different classes of devices. Just pay attention to the product class (desktop/mobile/LV) and product generation and the i3/i5/i7 designations will be appropriate.

Pentium as a brand name has too much consumer good will for Intel to drop it. Remember that Intel Marketing spent 20 years convincing people to buy them. I have met people who bought a Pentium-based notebook rather than a Core i3 specifically because of the Pentium sticker. And current Pentium CPUs certainly aren't bad. They're pretty much i3s without hyperthreading support. They're perfect adequate for light-use machines.

I jokingly tell people that Celeron is an ancient geek word that means "Don't Buy Me", but the fact that they continue to exist is mostly a statement to the levels of ignorance present in the computer-buying public.

On a per-core basis, a Haswell i3 is significantly faster than an i7-920, but the extra threads and dynamic overclocking in the i7 feature set make up for it. In day to day computing, the two are probably about equivalent. For thread intensive tasks like video encoding, the i7 is still the better option. Which just shows how completely insane i7s are, to remain competitive with mainstream desktop CPUs FIVE YEARS after their launch date.

You can get about 85% functionality from loading four specific APKs to get some Google apps on a FireOS device. You can also root it and load the full suite at the cost of your warranty. But some apps sourced from the Play store use Google components that won't work without Google licensing even if they themselves are not products of Google.

Many Android devs simply don't publish their apps on Amazon. I'm not a mobile dev, so I don't know why that's a problem, but it is.

You can tell people not to use third party stores, but there's a greater problem when the first-party option is completely off the table and the second best and universally compatible choice is wholly inadequate.

I'm more likely to use Spybot's, on systems that support it. That's mostly out of laziness. It's actually possible to do both. Spybot will append its list to whatever is already present, but functionally they're close enough that I don't bother.

MBAM does have an AV module in its paid product, but I think you're not making a distinction between anti-malware and anti-virus applications.The two things are distinct and primarily differentiated by whether or not the software in question tries to spread itself to other files or computers. I agree that anti-malware is much more important because it is much more commonplace, and in my experience there is no single tool that is actually worthwhile for both types of protection, but Windows machines do need both and are best served with best of breed protection from multiple products rather than a single tool that might only really offer worthwhile protection from one side or the other.

I'll also say that Spybot Search and Destroy offers a much more comprehensive array of malware blocking tools when compared to Spywareblaster and it should probably also be in your tool belt.