Reptilian homage-> slight bonus to beast-mastery techs, slight negation to human/diplomacy espionage/trade techs. Armies with a reptile gain slight morale boost, armies with a dragon gain large morale boost. Upkeep for magical scaly critters is lower, treasury and population in captured cities is lower, due to tribute to your reptilian idols.
might have to pick a sub-set of reptiles to be "attuned" to ... aka all citizens have faster movement in swamps, penalties when crossing desert. Black Dragon
Or experience no fear/penalties from caverns, 10% fire resistance, strength bonus Red Dragon
Or faster in deserts, slower in jungle, 10% lightning resistance Blue
Faster in Forests, more agile, 5% strength penalty, acid immune Green
slight strength penalty, slight innovation/dexterity penalty, immune to gold damage White
stronger and faster, slower build times, slight overall magic resistance and attunement (if enabled to use magic) -> Gold
Higher morale, lower attack -> copper
Higher desert defense, stronger morale -> bronze
Diplomacy bonus, mountain bonus, 5% weakness to fire, strength bonus -> Silver
Where Gold, Silver, and Red would cost slightly more, or simply balance them with the rest and have them all free.
Its also not a strech to think there would be certain groups of lizardmen attuned to each of the draconic races ... half dragons if you will. These could be rogue nuetral beast races that can be hired out as mercenaries. If you picked the Bronze subset of reptilian homage, for instance, not only would Bronze Dragon have a significant morale and health bonus while in your army, but your army would also benefit from a large morale bonus and lack of fear, if perhaps a slower initiative, while the Dragon would have near double initiative (all wait on dragon to make a move)
back to the rogue lizardmen ... you would have significant bonuses when hiring bronze lizardmen mercenaries, and they would have a speed bonus for being part of your reptilian homage. also, if you happend to have a bronze dragon working along-side you, the lizardmen would be imbued with divine valor, and recieve a strength bonus. (in addition to the army's overall morale bonus for having Bronze homage warriors and a Bronze dragon combo)
this could lead to diplomacy penalties with other nations, especially if their civilization has particular reptile hating traits. For instance, depending on the direction taken, a Bear Lords trait could either see the Reptile Homage nation as a familiar wild-men approach, or they could choose to view lizards as arrogant and barbaric, and have excessive hatred and being elitist towards bears. I think it would depend on the values of the opposing sovereign, and perhaps also alignment barriers.