By 4 weeks they should be able to handle wet cat food. (My Aya was about 1 week older than your guys when I found her and transitioned nicely to mushy kitten food after 2 days)
You can add some water to it and make mushy soup out of the kitten food. Put a little on your finger put it in front of their nose/mouth and see if they will lick it off. I had the kitten in my lap on a towel and a shallow dish or lid with a spoon of mush in it. After she licked the finger. I'd refill from the dish. Soon enough she toddled over to investigate the dish which of course smells like the same yummy stuff.
It took a few days of encouraging to get her to eat straight from the dish on her own (Aya had a bad cold and couldn't smell, so if your babies are healthy it might be easier). And they will make a mess of themselves and the dish etc... They still do best with lots of small feedings during the day. I only put out a tablespoon or so of food at a time. They forget where the food is as well as the littler box so best to have it and them in a small place, and you may have to put them in front of it.
Darn cute little rascals...
