That's really not a bad idea. The MIDI Output ports directly couple to the MIDI In jack (through opto-isolators). All of your devices see themselves as 'first in line' for receiving MIDI messages. This is the way to go for more complex MIDI systems, or as close as you can get to rock-solid timing. The MIDI signal is 'split' in parallel, and re-conditioned for each of the four MIDI Outs.
When you daisy-chain MIDI Out to MIDI In, there's always going to be some kind of processing overhead contrributed by each device. As a rule, newer MIDI devices are better at minimizing this delay than older, classic MIDI devices. But it's there, and it accumulates with more devices in the chain. You can usually get away with daisy-chaining 2,3,or 4 devices before you run into problems, but that depends on the components. The Eventide boxes use a Soft-Thru, so there's going to be some software processing involved.
Something else is going on here. It shouldn't be that bad (especially at the high end of your range). I do use an 8-Port MIDI Router on my rack, but the PitchFactor is daisy-chained on one port with two other MIDI effects. One is ancient, and the other tends to 'fall asleep' with any kind of MIDI Clock delay. The timing accuracy through all 3 devices has gotten even better with the PF latest update. And I "feed" them (from another MIDI port) with an FCB-1010.
One thing that I do is to isolate only the essential MIDI messages to each footswitch. Theoretically, that shouldn't matter. But the FCB-1010 can send 5 Program Changes, two MIDI CCs, and a Note value with each footswitch. Plus whatever may be happening with the two expression pedals. While you should be able to get away with 1,000-1,500 messages per second, it's a serial protocol. Real-world problems tend to creep in.
I also have Running Status enabled in the Global Configuration of the FCB-1010. Simply put, it can eliminate some redundant parts of MIDI messages. It doesn't appear to make a huge difference, but every little 'bit' helps in a complex MIDI system. You're competing with MIDI CCs, PCs, MIDI Clock, Sysex, etc., and it's all travelling down the same single-lane highway.
The reported Mobius timing seems way out of line. I got to look at the documentation a little (and now I know why you chose CC 93). That part looks right; I don't think that you're "doubling" your tap tempo input (but I'm not positive about that). You might want to check the Common Parameters [PARAMS -> TapDiv], and see if the presets you're using are set to Quarter Note. Since this is saved per-preset, I would think you'd set tempo to Global for the system that you're creating here.
Maybe one or a combination of these things will help to get your devices back in line.
