Who should i promote

Depends on the rest of the box. Do you have a green mage already? a physical red? If you have one or two of each of these roles already id go for powering up someone good over adding someone new.

Hana and Chrom. Chrom is a very defensive unit and his attack is almost like Lucina's. Ayra can make up for his speed, especially if you got Life and Death 3 on her.

Arden

Arden

None of them are worth promoting at this stage of the game.

Promote Arvis if you haven't already. He hits pretty hard and doubles as a healer. And he debuffs 3 stats from any distance. Even without inflated TT stats he is good. He might have a permanent spot on all my future Tempest trial teams because of his Renewal 4 skill +ardent sacrifice

Sometimes, you might want to take inventory to see what types of units you need. As for Hana, sometimes I promote someone to 5 just for inheritance, so I can see why that's a consideration.

I say do Hana, and then do one of the three in the field that you need the most.