1) Mobile internet access / WiFi hotspot:
Feature phones as old as the Ericsson T39 (note the absence of "Sony" this old piece predates the merger) were already able back then to work as GRPS modems over infrared, bluetooth, or USB (but the USB cable was expensive and rare, so bluetooth then).
And this antique only has a couple of text lines on screen.
Camera: it's not as good as a dedicated camera, but it's better than no camera at all, and is really handy for taking quick photos of things if image quality isn't paramount.
Note that feature phone used to have cameras too. Feature phone introduced camera before even smartphone where started.
Same goes for a lot of other things you mention (email, games, alarm clock, calculator, etc.)
I think games and alarm are the two first features built into phones.
8) Texting: For close friends this is pretty handy for staying in touch at times, though I don't use it that much. Smartphones make this better with an actual (on-screen) keyboard, instead of the shitty dumbphone method of using the 0-9 keypad to try to type messages.
Partially solved by several techniques. For example, one available backthen on the a fore mentionned Ericsson (still available on all subsequent Sony-Ericsson feature phone) - volume rocker works as a kind of "shift" key. Using combination of volume + number gives you directly the letter you want instead of repeatedly pressing a letter. Gets a bit time to get used to it, then works as fast a typing on a keyboard.
Some provided external keypads (again Ericsson had a "chat board": full qwerty keyboard), if your finger arent's too fat, it's fast than a virtual keyboard.
9) Playing music (like a "walkman" if you remember those): I can store my entire music collection in my phone and play anything I want through headphones, like when I'm at the gym.
The whole MP3 craze began much earlier before Apple re-invented it with their brand of players. As soon as MP3 player stared being popular, phone started offering the function, some phone even had a dedicated separate physical interface for that. Close the clam shell: you have buttons and a small monochrome screen to handle playing your music. Open the clam shell: feature phone with color screen.
Flashlight: It's handy to have a flashlight on hand sometimes.
Can you actually think of a phone that DOESN'T have a lit up screen? People have been using it as improvised sources of light for as long as I can remember.
The only thing brought by modern smartphones is *white* light (as they can abuse their flash for that, where as old monochrome phone screen tended to have blue, green, orange, etc. backlight color).