The cat's are terrified. Give the poor things a chance!
Put them in the spare bedroom your 2yo must not have access with food water and litter facilities. Toys and scratching post are good extras.
Spend 5-10 minutes every couple of (daytime) hours in there quietly, maybe encourage them with fishing rod toys and treats like tuna and plain cooked chicken. Allow them to come to you initially, get them used to being stroked and brushed.
After a couple of days, take your dc with you under very strict rules - no loud noises, no touching. Any rule breaking, come straight out.
They'll probably be curious by now so leave the door ajar. dc may not go into that room, but cats may come out. If you want a cat to like you, ignore it. Direct approaches, loud noises, making yourself bigger (eg arms outstretched for a cuddle) and bared teeth are all aggressive in Cat Language, so your 2yo is basically telling your cats that they're about to be torn limb from limb 
The rescue Centre should also be able to advise you, but give it a couple of weeks in their safe territory before you write them off.
Oh, and a cat can get over a baby gate easily enough - It's how I keep my bunny out of my living room. Cat is next to me on the sofa!