Re: Singers and their equipment
Singers with only a mic join bands all the time. My band's singer bought a small PA because he felt guity that everyone else was spending money and lugging lots of stuff while he got off scot free. He's a good human being.
In most band's I've been in, either we've used the venue's PA, hired PAs or a manager/engineer we had brought his along. In one band the singer would often saunter in after everyone else was well into at setting to. He's just have his Shure and set list. He'd help (or pretend to help or talk to people actually doing stuff) for a couple of minutes and then would go off socialising.
Nice work if you can get it.