Well,I think that in your case the best one would be an Expert Sleepers ES-8, that way you can use it as your audio interface. It has 8 outputs and 4 inputs.

Another very good option is Hermod, which also doubles as a midi interface and does a lot of sequencing. Mutable Instruments Yarns also could serve this purpose.

The limitation with the Mutant Brain is that it only has 4 CV outs, the others are Gate/Trigs so that limits what you can do with it. Yarns, for example, can be configured so that any output can be any kind, be it CV, pitch, gate, trigger.