Good stuff Jason! I have run lists with a good amount of knights and Carnosaur's and here is my feedback.
The firelance battalion is cheap and cool, but isn't as powerful as it seems at first glance. The charge bonus is great! But the damage isn't very consistent. They have low number of attacks and after you charge your dmg goes down. I've found more success with buffing them under the Bloodclaw battalion. Here is some math:
5x Knights under 3 Scar Vet Buffs in Bloodclaw:
5x Lances/Blades
25x Vicious Bites
-10x Powerful Jaws
reroll all hits of 1
average of 14-15 wounds (at - rend)
5x Knights with Firelance:
5x Lances
10x Bites
5x Jaws
average of 6-7 wounds with maybe 2 mortal wounds the turn you charge.
The thing that I found was, the turn you charge and you don't roll a lot of 6's to wound, the knights just don't cut it. Also if they get bogged down in combat, the firelance buffs are gone, when the Scar Vet's can buff them as long as they are alive and also buff all of your other Carnosaur's. Either way knights are a little underpowered, but I have found a little more consistency with buffing them under the Bloodclaw and then having them hunt down light infantry, rather than going for the hailmary mortal wounds on bigger/tougher creatures (That;s what the Carnosaurs are for

)
This limits your Carnosaur count to 3 but if you went Bloodclaw I'd go:
2x Oldblood (4 extra attacks on every leader is insane.It means with the reroll, Coldone Vets are hitting 14 times lol)
3x Cold one Vets (mini Carnosaurs)
1x Scar Vet Carnosaur
15 -25 Knights and other units to taste!
That's just my experience and input. Either way this is exactly how i like to play Seraphon. Smash mouth