shipping is entirely up to you, but wheter or not it ever becomes reality is yet to be seen. I can kinda see the NaruSasu vibe for Leiko and Momo in the loud, outgoing friend/quiet, arrogant friend kind of way, and between Ryu and Leiko in the rival way. 

For annoying talkitiveness, I'd suggest lots of talking that tends to drifts off the initial topic, or just have her be a mile a minute motormouth.