flier team requires very specific units like Hinoka to be optimal (only source of Hone Fliers). And the one ranged flier, Spring Camilla, is no longer available. If you've got a +atk Cherche and a spare Brave Axe+ you can start forming a team around her though.
You can make a very competent cavalry team entirely out of free units. Xander, Cecilia, Camus and Ursula is quite solid but requires a ton of feathers as well as Blarblade and Gronnblade tomes. But it's doable by anyone, eventually. I use Eldigan instead of Xander, and I would've used Reinhardt over Ursula if I ever found one. But this team stomped Tempest Trials for me all the way to 100k and finds arena very easy. Just has trouble breaking the 4800 point barrier.
I have a +DEF/-HP Reinhardt. Is that OK?
Also stats should I want for Cecilia. I have a lot.