I ran OpenFire for years with only one user. It was always extremely tight, and sometimes too tight (with crucial processes getting killed because they ran out of memory). Your mileage will most probably vary, but for me, I had no choice and had to switch.

I only have a VPS at my disposal with about half that amount of RAM (which also has to do other things).

Or Prosody if you don't want to waste lots of resources for a server that will only have you and your parents on it.

There are two Dvorak keyboard layouts available in most major OSes: plain Dvorak, and Dvorak+QWERTY. The latter switches to QWERTY while one of the control keys or alt keys is pressed, allowing you to keep your shortcuts.

Personally, I just re-learned all my shortcuts, and I don't really have any problem with those any longer, neither in VIM, nor in any other program.

As for Dvorak keyboards: you're better off without them initially, because they'll slow you down at first (you keep looking at your keyboard). Once you're trained, they might be useful for entering shortcuts quickly. I just rearranged the keys on one of my Apple keyboards, which works for this type of keyboards (all keys have an equal slope). You'll want some sticker on the homing keys to locate them fast, though. But anyway, the keyboard i mostly use is still laid out in QWERTY.