The MIX BX is a large module for a smaller build like this. Take a look at something like Cosmix which is half the size and still a very powerful mixer. Also maybe Bitbox Micro instead of Salmple which saves 3 more HP...now you have 22HP extra. Maybe add an effects module like FX Aid Pro (14HP) and you have 8HP to add Pamela's New Workout as a clock source for everything.
JB