TC is only an input and when it rises the FDC reads or writes but does not transfer until the end of the current sector and then terminates the operation successfully. That works even in PIO mode although that isn't relevant to the PC.

Wouldn't really bother with drq/eop whatever lines, that's all bus level and you shouldn't really care for emulating that.
My dma channel read/write routines can just return a value if terminal count has been reached during this read/write action and the floppy goes into the result phase then when that's encountered with enough all bytes done.
If the floppy encounters any kind of error with a dma not being setup correctly or not enough bytes being programmed you just go into error mode and the controller would need to be reset anyway.