1. Can an A4000 work with without Fast RAM (only Chip RAM) ? If so, can you confirm no jumper has to be changed ?
No problems, no setting jumpers; should work just fine.
2. How do I know if a bare RAM module of the right dimensions, memory and speed will be suitable as Chip RAM ?
Any double-sided FPM (preferably not EDO) module should work. I have used 8MB SIMM's as chipram without any glitch
3. Can I use as Chip RAM a 4 Mb or 8 Mb RAM module (assuming the computer will only use 2 Mb) ?
Yes, you can. Although the Amiga is picky, not any module will work. Single sided SIMM's will only work as 1MB chip, double sided should work as 2MB.
4. Can an A4000 work without a hard drive (only a floppy drive) ?
Sure, no problems.
5. Can you confirm that no hardware change (cable or jumper for example) is required in order to use a low density floppy drive instead of a high density drive as the only internal floppy drive ?
Confirmed. Jumpers need only be set if you use a HD and DD floppy at the same time.
6. Without the IDE and floppy cables, what should the A4000's behaviour be at the switching on ?
Bring up a purple Kickstart screen asking you to insert a floppy.
