Look up the weight limits and learn how to pose them and what to look for (body type, ear length, etc) before deciding if they’re good to breed for show quality.
Looks like your doe (broken?) may be a “bud” (big ugly doe) which is good for breeding with less risk of doubling the dwarf gene (fatal), but isn’t good if your buck is a “bub” (big ugly buck) since you’ll have a high chance of offspring that are too big and heavy for showing.
I used to raise pedigreed mini rex and they did well in shows, but I didn’t show them myself. I did breed to standard and make sure my stock was quality, but it’s been long enough that I don’t remember the specifics anymore.