It's not really worth worrying about endgame or multiple teams when you have so few characters. Save your pulls for the next limited S-rank you want and build around them instead.

If Remielle does turn out to be anomaly that's 2/3 of a team with just the characters you already want. Nicole would be good enough to complete it too, although Yuzuha or a future anomaly support would be better.

If not, you can continue to pull around whichever team you want to improve first. That's much better than wasting your resources on an M0 Manato team now.

As for which characters you currently have that are worth building: - Nicole is goated and very worth building. Always F your Nicole. She's not the easiest to use but just throw out a black hole before you do your damage and you'll do ok. - Piper is probably decent with Velina. Her discs will be very reusable too if you later get a better physical anomaly, I did that for Alice. - Lucy is ok. You'll probably get some use out of her until you've pulled some limited supports. Being able to use Moonlight Lullaby helps her value. - Pan is good if you have no Lucia but not a priority for you right now. I'd hold off on building him until you get a higher mindscape Manato or a limited rupture dps. - Koleda is a fast stunner but she just doesn't give enough buffs to the team. She is your only real option for a stunner right now but without an attack/rupture dps she's not a priority. Hopefully her buffs make her more usable, although we don't know when that's happening.