1/The printer needs all the cartridges inserted to work. In theory you could leave the empty colour cartridges and override the level sensor though this means you lose that function.
2/ The chipped ones should work 'out of the box'. Unchipped ones require you to remove the chip from the old cartridge and put them on the new cartridge. This can be fiddly as they have to be perfectly aligned and unless you buy a re-setter the level sensor also will need to be disabled.
I use a CISS on my IP4500 and it just works. It has been topped it up once in 18 months.