Most of the requirements are de facto standards nowadays
(after all, we are talking about technology that's around five years old now).
You'll need an IBM-compatible PC, (usually) a hard disk, and EGA at least.
More information on each game is below.
Avaricius claims to support a mouse. Ho ho ho (the mouse control is
laughable).
You can run Avaricius off a floppy, but I wouldn't
recommend it unless you have to.
Avalot can use VGA if you have it to give you nicer colours. Not much, I know.
Also you can use a joystick for control, if you have one, and mouse support is
much nicer than in Avaricius. BUT some operating systems (OS/2, for example)
seem to eat the mouse pointer and mess up the screen. Also on the subject of
OS/2, the game will refuse to run off an HPFS partition (I don't know why);
use FAT instead.
Spellchick actually runs quite nicely off a floppy. Note that
it was built on an XT... you have been warned; it wasn't designed for
refresh rates and things as high as they are today, and the screen might
be a bit flickery.