Jump on this thread as I read recently very interesting things about reptilians that IMHO should be taken into consideration... maybe you did already, in this case sorry!
So I discovered several things I didn't know or know only partially:
- Most reptilians communicate with odors and postures. Hence their prejudices against mammals would be very justified by the fact that such lowly creatures smell wrong and cannot stay put in proper positions.
- Reptilians are really more stupid with low temperatures and humidity, bringing therefore a social regression if such things happen.
- Croc mums care for their eggs maniacally, snakes coils around them, while other reptilians do not and simply bury them, but return to watch them often. Eggs nurseries should be a fundamental and heavily guarded feature in reptilian societies, also because most reptilian eggs have softer shells than birds..
- Crocodiles embryos "speak" in egg to tell mommy they're ready to hatch.. Turtles and crocs have complex vocalizations.. Famous reptilian singers should be a feature of their societies
- Many croc parents raise juveniles together (male and female) or even collectively, but other reptilians do not, juveniles are already capable of living on their own, but "four babies form a group of siblings called pods, which stay together for months. The rub up against each other frequently, they groom each other and sleep together". It's likely that the pod would be a social unity lasting for life, maybe the most important one in reptilian society.
- Pods play together, and play behavior is common in reptilians as in mammals and bird..
- Pods have leaders, but the leader do not "command" the others, he rather protect them. Maybe mammals see reptilian hierarchy and found it oppressive, while from their point of view it's a matter of brotherly responsibility. Also brothers have been observed to be ready to sacrifice themselves to protect sisters.
- Reptlians are very good at solving problems and use tools too... reptilians should have technicians and engineers!
- They have complex and diversified mating rituals that include competition between males and females too, exclusive relationships, changing of colors by males, courtship dances involving hundreds and more.. so summer mating season should be an interesting time in reptilian society...
- Families could live together or near as happens in mammals.
I found all this quite important because the typical depiction of reptilian societies in fantasy world is always that of cold, calculating, emotionless beings, inflexible enemies of men.. while they could have several prejudices against mammals, it's also probable that men have many prejudices against them...
A friendly mogrethian who understand humans better than his countrymen, willing to aid PCs and explain them Mogreth society would be, IMHO, a great starting point for a very original adventure... just my 2 cents..