Put it this way, an adult (1+ year old) meat rabbit here weighs as much or more than an adult cat. Your rabbits look smaller than that. By a lot. However, that is NOT going to be a problem--you are just going to breed toward what you want, and eat/give away/sell the rest. Pick ONE main goal and 2 smaller goals for your colony, and don't keep any that don't meet goal 1, and then use goal 2 & 3 to decide between the rest.
For instance, if I am breeding for meat, and my rabbits are all already pretty healthy, I want a heavy, fast growing rabbit with a big butt/loin. I will evaluate everyone the day I am ready to harvest and then only keep an animal if it is heavier/bigger than my current breeders were at the same age--keep records and weigh them or measure somehow so you know for sure.
second and third things might be temperment and fur quality. If I have 3 big hefty boy rabbits at butchering age, and they are bigger than my buck was at that age, or at least as big as he was, I next pick the best by fur and temperment. Since my rabbits are a fur breed I actually have specific things I want to see, like consistent color and thickness.
As part of my job I breed animals for research, and there are various genetic goals I might be breeding for--the number one thing to realize with something that breeds fast (like a rabbit, a mouse, a worm, or a bacteria) is that you can push the colony to be on average bigger or smaller, whiter or more colorful, stronger or sicker in about 3 generations, just by the choices you make. Where you start is not nearly as important as what you choose to keep going forward.
If my rabbits are weak and die a lot, I am going to reevaluate my goals to be all to do with health--and look for healthier stock to buy.