I have the BitBox. I also like that it has two alternative firmwares that allow it to be a wavetable synth or a multi-effects box.
The ER-301 and Assimil8or are good choices if price and rackspace aren't an issue.
How fast do the LFOs on the Hermod go and can they be reset or sync'ed?
A second case seems more logical as this rack is pretty much full. I'd find a big-o-rack and keep the Intellijel as maybe a core rack or your performance rack aka the rack where you sequence and control the rest of your system.