Is it important for all the speakers in the array to be the same size and brand?

I mean suppose you upheld the c-to-c but some of them were Sammi's and some were Daytons, and suppose you made a woofer array where the bottom speaker was a 12 incher but all the ones above it were 7 inchers.

That seems crazy, but if you are using electronic crossovers, would it be?

Marlboro

Same tweeters
Same midranges
Same woofers
Same subwoofers

I wouldn't mix different tweeters, mids, woofers.

I woldn't make a woofer array of 7" drivers, then add a 12"
- just because - into the same box doing the same job. Either
bandpass both to do their own seperate job or make a full array of 7"
or a full array of 12".

Common sense rules.

If each goes into a separate enclosure, and if each is matched by sensitivity, and some other T/S qualities,

Other than it seeming just "wrong", Why is it :" Well.....that's just wrong!" Why....???????

I think mixing tweeters and mids might be more wrong than woofers, but I've seen people adding a piezo to an other wise line...but woofers.....

Marlboro

If you want to create a different sonic signature from the
loudspeaker, then create different ones by using your EQ and
crossover to alter performance, and you can always revert back
to a normal configuration too.