You could try rolling for Aisha. As you probably know, she's the most broken unit in the game. She's the only black featured in one of the banners, so now would be an ideal time going for her. Whether it's worth the effort and missing out on some of the stuff that accumulated on your account (including the "rainbow fairy with blue hair" which is a time fairy by the way and reduces the cost of a unit by 1 guaranteed) is up to you.

If you decide to stick with your account, the leveling priority doesn't change much. You can use Grace as your main tank. Leona (plat rearguard tactician) is very useful and should be leveled early. Once you raised a solid core team you can level Sabine (plat rune fencer) so you have a decent melee support. The other units are fairly niche, so you can ignore them for now.

Early game goals are the same. Aim for H dailies and get to Oasis and then to BS2 ASAP.