I have FT601 on my own custom board with Artix-7 FPGA. When FT601 is configured in 1IN/1OUT (single bidirectional pipe) mode, I was able to get ~330 MBytes/s of "real" read bandwidth (meaning this was a rate I was getting an actual data out of D3XX API, so all overheads are factored in), same chip on a same board with FT in 2IN/2OUT mode - I was getting ~220 MBytes/s of read bandwidth out of a single IN pipe. The board used FT601 with 32bit bus running at 100 MHz and with Vccio of 3.3V.

Please note that you can configure FT to only have a single IN (or OUT) unidirectional pipe if you don't need two-way communications (or if 2 GPIOs are enough for your OOB needs), this will likely push the bandwidth towards 400 MBytes/s or so.

So that's going to be more than enough for your application. Infact you can probably get away with 16bit model, but don't quote me on this.