SQL Server : multiple databases with transaction log on one SSD array
Changing from sequential to logical read / write patterns is far more harmful on rotational drives than SSDs.  Because SSDs have no read heads, latency is much lower, even on non-sequential reads and writes.  You will take a performance hit if it's not sequential, but with higher-end SSDs, you'll be able to get close to or saturate bus speeds (SAS / SATA) on the system.  You'll need to make sure that whatever you're driving your array with can sustain the I/O.  I've found CrystalDiskMark benchmarks w/ 4k @ 32QD have been accurate indicators of performance on a busy system.  All that said, if your SSD array can sustain the same IOPS across all logs with random I/O as what your rotational drives can do sequential, you'll be fine.

I don't have any experience with FMDs vs SSDs.