That's pretty impressive that you've gotten them to eat solid food so quickly! My last set of orphans were a bit spoiled (OK, so they are still spoiled). Since they didn't have a cat mom anyway, my dear friend adopted 2 of them (Jake and Elwood) when they were 5 weeks old and took them to her home in Denver. She wanted them before they were weaned so she could develop the meowmy bond with them at a young age. Her 2 boys were eating canned food within a day for her.
Then there was my Muddy and Koko. At 8 weeks old they refused anything but the bottle. DH and I were heading out of town (probably a family wedding) so I decided to board them with our vet tech (she was willing to continue to bottle feed them for me). I apologized to her about not having them weaned and she just laughed at me. Turns out they started to eat solid food the day she took them into her home. She just got firm with them when I could not do it. It was actually a bit embarrassing.

Orphaned kittens don't always develop cat habits like normal cats. Muddy is a very good boy, but when he does act up, he has a very difficult time comprehending the word "NO". He gives me an almost confused look when I try to discipline him. Koko has a tough time relating to any other cat in my house other than Muddy, because she is full of play, but has no boundaries with it. She annoys the other cats when she tries to play with them, and is only tolerated (to some extent) by her brother. Jake and Elwood are allowed back yard privileges (they have a tall fence in the back yard), but panic if they are outside and need to go to the bathroom - they were so well trained in using the litter box that they don't know that they can actually pee anywhere else.
So advice for you at this formative stage in their lives: do what you can to set their boundaries on what you deem as acceptable behavior or they may never learn it. Hindsight tells me that I should have corrected Koko when she pulled her WWF moves on her brothers. How does a mom cat correct their young? With a hiss and
gentle scruff, or simply by holding them down with a paw until they settle down. I learned about this after the fact.