1 - It will accept a 68882 (PGA) 25Mhz or 50Mhz FPU
2 - Any size, but without some patches you will only address the first 4 GB by default.
3 - Like 95 % of all Amiga games will run. Use WHDload software together with iGame for a good gaming setup.
4 - Some Amiga games will require you to use either a keyboard or/and a mouse. Of course, that depends on each particular game.
5 - You should use WinUAE, attach the Amiga harddrive to a PC and set WinUAE to recognize that drive and disable the safety check, so that you can format, install your AmigaOS and some games from within your PC.