Any time you put a large lot of anything directly into your tank, you could be asking for trouble due to the bioload.
I would say if it's just for the weekend, feed them well Fri night before you go, then again as soon as you get back Sun night. They will be fine. Many people skip a day between feedings. Two will not hurt if they are healthy.
I attempted to do much the same thing years ago when seahorses were mostly all live caught and would eat only live shrimp. Knowing I would be gone for a long weekend, I shipped in and added some 50 live shrimp to the tank (this was a large tank with numerous horses). Unfortunately, most of the shrimp did not make the trip well and died before the ponies could eat them. This caused a catastrophic chain reaction which led to the entire tank crashing, and the loss of 9 horses. I will never make that mistake again, and blame myself exclusively for their deaths.