My guess with Lexi is an aussie X sheltie or collie. Sometimes later with personality and gait you can get a better idea as different breeds do have different gaits.
Trip could be an aussie, could be an aussie x border collie or even could be a border collie as they do come in a blue merle so not all blue merles are aussies as even collies and shelties come in that coat. My late Phoenix was what we think a blue merle border collie but from a merle to merle breeding so she was a homozygous merle as she was deaf and had limited vision, she did however have a beautiful full collie coat which some border collies have. She was 35 lbs. She was found at the side of a road as a wee puppy and then at 1.5 given to the humane society and at 2 I found her there. She did no show well so people just passed her by. She was very shy then so ran inside when people looked at her in her run
But for what ever reason maybe the fact I was not looking for a 3rd dog
she and I hit it off right away making it impossible for me to leave her there. The human society was thinking aussie because of the coat but her movement and behavior screamed BC and many of my agility friends who own BC's felt so too.
I am also posting a photo of two blue merle BC's they are old in this photo but I knew the breeder and knew each as a puppy. The breeder had a blue merle male and so her litters usually has one or two in them, These two are brother and sister.
What ever the breeds of your two pups they are both adorable!
Phoenix with Dazzle( black and white silken windhound)
Two blue merle border collies.