increasing inputs into brain v2 busboard

Hello everybody

I Have questions re expanding the number of inputs  into the brain v2 bus board.
I have maxed out the pin header connections on the brain v2 found myself still wanting.

Reading around the forum the typical solution is to employ the use of a second brain (v2 or junior) however this is not possible to do at the moment as their does not appear to be any available.

So scratching my head whilst  staring at the brain v2 and the bus board for quite some time i thought I wonder if it is possible to  place a multiplexer inline to each button/ LED header/analogue  header on the brain v2 bus board  so allowing for larger matrices via a multiplexer to be connected to each header on the  bus board.
in principle i would like to increase the number of analogue inputs as there are up to 64 unassigned midi cc/ note numbers. I would also like to increase the increase the number of LED's up to 282.
if any body has any thoughts on the above mentioned or another work around apart from the second brain option  please feel free to message me or post a comment.

Thanks for taking the time to read this.