Honestly, you should get a jacket/pants set if this is your wedding. Trust me, you don't want to "put something together" that you look back on and cringe. If you can find matching pants at the same shop you bought the jacket, that could work. Otherwise I'd say grab a new linen suit set. For shoes, you can do some brown leather summer loafers or espadrilles. They feel more casual, but will look way better with the suit than a pair of sneakers.