i'd be very down for them to meet!! reiner is actually quite willing to reveal that he can turn into a titan; he just doesn't bring it up unprompted unless it's something an ally needs to know. (for example: he brought it up before venturing into a segment with someone, basically going 'btw if things go bad i can do this.' but he wouldn't bring it up as a Fun Fact over coffee.)

regardless, lahabrea being Very Tall would probably be somewhat comforting to reiner? he misses having his tall bff around. 😭 but yes, would be happy to toss them together and see what shakes out!