I have had a similar challenge in a band with the guitarist using the bass line as a solo, also because it was written first. I've said in the past that I can't write the bass line for one of the later tracks until every thing else is in place, as I need to lock in with various rhythms rather than leading - took over a month for the guitar part to be written, as opposed to the usual few minutes of listening to the bass
Also had a similar superior attitude from a guitarist that wasn't much beyond beginner basics.
Having said that, the majority of people have been fine to play with and be around, and of course it can go the other way with everyone gelling nicely for a few months before it all goes horribly wrong. Sometimes its getting on well with the people that makes it all worth while other times it's the music and being on stage - it is nice to have both if you can though.