Thank you for adopting two beautiful rescue kittens, (I call them beautiful even though we haven't seen a picture of them yet because you know darn well that they are beautiful.)
If you don't know the exact age, yes posting photographs will help, many of us here are pretty experienced with judging cat ages - stages.
It is true that cow milk is not the best thing, cats are lactose intolerant, and a product known as kitten milk is good for them. Depending on how young they are, they may not be very used to eating solid food yet? When I was transitioning my kittens from the teat to the bowl, I took a kitten blend of wet cat food, (kitten blend usually has higher protein) and mixed it with a bit of water to make it a bit wetter, not soupy exactly, but just wetter, and I also tried mixing some wet food with kitten milk in a separate bowl.
If they really really aren't drinking, that might be a problem, you don't want them to get dehydrated. You might want to try a bowl, a plate, you might want to try tap water, you might want to try distilled water or spring water, you're not quite sure what the cats will be used to or what their tastes are. The most important thing is to get them drinking even if they're not eating just yet.
I put their wet food on a plate because I thought they might have difficulty figuring out how to use a bowl because they were small. It was a messy time, feeding meant that they were stepping in the food and getting it all over their little faces but that's okay. Just gives you an opportunity to bond with them as you clean them up.
I had to have taken 10 million pictures when my kittens were born because I knew how quickly they would grow, and gosh they did! I hope that you enjoy every moment with your two new additions.