Hiya,
I've never heard of this conflict, try asking over on EAB.
There are a couple of things you need to know about the FastATA, first of all it's a bit of a bitch to install, secondly you cannot use SATA for your boot drive, thirdly it's really difficult to install them with an Indivision AGA.
I brought one myself and it's still sitting in the box
An IdeFixExpress is a much easier solution but they are hard to find.
The Apollo's IDE transfer rate isn't too bad anyway, with a RemApollo + patched scsi.device + SpeedyIDE + PFS3 you should get a reasonable speed without any new hardware.
BTW the Apollo can only take 32MB per slot.