Activate / SIM swap / restore (transfer) data - does the order matter?

Just got 2 new phones on existing plans under the same account (S23 Ultra, one 512 and the other 256, they're both upgrades on the DPP). We haven't activated them yet, because we want to swap the two devices. In which order should we do that? Verizon's FAQ says "must pay any balance due" (what balance?) and "must contact us", which confuses us. We thought we can just swap the SIM cards, based on some posts here, but will it cause any problems? So which do we do?

Activate both as they are, then swap the SIM cards (with or without calling Verizon?), then transfer/restore data the back up from the old phones? Or swap the cards first, then activate? Or transfer/restore data first and then...?

Thanks in advance!