1. 8MB atleast would be recommended:
2. Zorro2 memory works, but in practice slows the 030 down as its much slower then mainboard memory.
3. ZIP RAM pops up on ebay from time to time, the other option is a ZIP-to-SIMM adapter, they might be harder to find though.... with DIP RAM i think you are limited to only 2MB Fast
4. The Indivision can create higher res output modes and pixel double, personally i would just save yourself money and use the onboard VGA output it works pretty fine.
5. lookup the SCSI2SD, thats the way to go for storage solution imho, silent, dont have to rely on 20 year old harddrives, and the speed is fast enough for nowadays Amiga uses.