What are the chances of recieving Penguini, Golrock, Ultimadon, or Rexo from the first egg because I’ve restarted over 100 times and haven’t even gotten them or a single legendary for that matter… 
I think last biters are only available on Rare Egg, having Super Epic as starting monster is good enough specially with Twin killer skills, 
The devs also drastically decreased the chances of getting a legend first roll, to prevent this precise thing from happening. Honestly, you’re better off just starting with a super epic than wasting your time trying to start with a legend. Make sure it’s a good one, like a throw/bloodcraver or a twinkiller.
And here are the lists of legendaries you can get from the normal egg and rare egg respectively. So the biters are indeed inaccessible in the normal egg, again the devs did it to prevent people from rerolling for a cheap easy start. Challenge is a big part of playing a game, embracing it will improve the experience, take it from me.
well i got one fresh account with cyberdrake if anyone wants i have no use for it
and trizar
I sent you a DM