Hi Dishwasher
Usually the r. hand parts on the keys fill out the bass end of a song pretty well. so I wouldn`t worry too much about your lack of a bass player at this stage. In addition any modern midi keyboard should be able to chuck out a reasonable bass guitar sound for the tunes that really need it.
Regarding your guitars, electro acoustics are the way to go - if your acoustic does not have any form of pick up, I would get one fitted.
It is so much easier than faffing around with a mic for the acoustic on stage and dealing with issues like feedback, positioning etc. The sound won`t be as perfect as a well mic`ed, high end instrument but it`s horses for courses. Save the fancy setup for the studio or when you`re famous enough to have your own guy to set it all up while you chill in the green room
As for the choice of music - basically play what you
really like. This may call for a fair bit of negotiation within the band as well as a certain amount of give and take between members. Believe me though, playing stuff that you can`t stand gets stale very fast - especially given that you`ll have to rehearse it till you can do backwards before you even play out with it.
As mentioned above, a basic PA will probably serve you best - just run everything through it ( the drums will probably be loud enough !)
Make sure that whatever you get has enough inputs though - Mic inputs for vocals and line level inputs for the keys and guitars.
Electro acoustics do work with effects - watch out for effects that boost the gain such as distrortion or overdrive though - they can cause problems with feedback. Might be worth your friend getting an electric guitar rather than another acoustic - it will give you a bit of tonal variation and may be more versatile in terms of the sound you can coax from it.
Regards
Will