I saw pictures of your morkies and they are just adorable.
They do get lighter as they get older. They look so much like our morkie Polo when he was born. The breeder sent me pictures of him and his litter mates before we even got to choose him. Polo was the runt of the litter, my neice who lives next door bought Polo's sister so they get to play with eachother. I also have a yorkie named Chanel and they all get along just fine.
If you want to see pictures of Polo they are in my album in my profile, you can also see what they looked like when they were three weeks old.
How many pounds do your morkie's parents weight?