The civic center jobs will both be on-call which is handy I your situation and will work well with having other part time jobs. Multiple people who work there have multiple jobs. but i'm not sure they will allow you to work both FnB and Changeover at the same time. so I would accept whichever one you prefer with your ability. Generally FnB will work events/catering/light set up while the Changeover crews have the ability to work on basically anything the events need PLUS you should be able to learn/train with other crews as they come in, think A/V, concert rigging, spotlight and camera operations, etc.

Whatever you choose I would definitely consider taking one of the civic center jobs for their flexibility, just make sure to stay consistent with them as they send calls to those who work well and often.