You can actually find a jacket for both situations but it will be hard. The most important thing is a good fit in the shoulders (not too tight but good enough to wear with a sweater. The thing that will be in question is the fit of the chest in both scenarios as it can be too tight with a sweater.
sandals are fine but they get too much heat here because they are abused too often. I wear sandals or flip flops mostly by the beach, gym lockers, pools, quick errands, etc. A convenience thing really and never with socks
I would not rock them mainly because of the red since it gives it a clownish look. Otherwise, maybe with dark wash jeans and black shirt it can give you that party look. With that said, it depends on the shine of he suede as well..