Team suggestions?

For what exactly? In general Azura and hector have pretty good synergy since she can help him move and cover him against reds. Brave Lyn and Reinhardt are both pretty good unsupported, but if they are horsbuffing each other could make a nice combo for hitting against DEF or RES, you could throw Olwen in as well for more cavalry buffs though if nobody is doing Blarblade stacking defense on the two canons might not be THAT important, but still nice. What the team is getting built FOR matters though. If its just generally what will perform well Id say azura, hector, classic Lucina, and brave lyn should be pretty user friendly. Maybe sub brave lyn for a good caster if you're worried about dealing with tanks.

My Olivia, Reinhardt, Brave Lyn w. Brave Bow, Julia team has been very good for me lately.

Reinhardt and Brave Lyn make a great pair, buffing each other with Goad Cavalry and hitting both Def and Res really hard between the two of them. Julia with Breath of Life skill and Breath of Life seal heals adjacent allies for 10HP every attack she makes, which is great for topping up HP during Chain Challenges while retaining reposition type support skill on the healer. Sometimes I even wish she had less attack so she could do more double attacks for healing with Olivia.

Speaking of Olivia, she gives you better anti Green capabilities than Azura, and a full RGB spread alongside Reinhardt and Julia. Even if you take Hector instead of Julia, Olivia might be the better match for your team given that you already have such strong blue units available.