That will only work if the Deepmind 12 can send a clock over MIDI when its sequencer is running. If it has that capability, then yes. However, that's sort of a 'hit or miss' function...some synths do, some don't. However, the Mother32 does have the capability to send a gate pulse from that output point when its sequencer is running, so you can lock the Voltage Block up with that and sync it wit the Moog's sequencer.
As for interfacing the Deepmind with this, though...again, the Expert Sleepers FH-1 will allow the DM12 to directly connect to the modular via USB, since the FH-1 operates as a USB Host, unlike the Doepfer interface which has to connect TO a host, such as a computer, etc. Now, while I can't find a direct reference in Behringer's lit to what gets sent/received via the USB, I'm going to guess that that signal is a lot more comprehensive than the MIDI ports, and likely does include clocking signals so that it can lock up with a computer-hosted sequencer. If this is the case about its USB signal, then not only can you lock the modular to the DM12's clock, you could theoretically clock your entire system via the DM12's clock, and that includes sending sync/start-stop from it to the Mother32's sequencer as well. But you'll need to check on that one spec aspect to make sure.