I wouldn't. You'd like to have both sets of elements working in the same fashion; with an array of mid-basses and a single tweeter you'll end up with the mid-basses working in the nearfield while the single tweeter is working in the farfield and it just won't sound right. The best idea is to either go all array or all point source. In your case I'd go MTM, to get the midbass sensitivity up closer to that of the ribbon.