I would do but I've already purchased the VSF return back to the States.
Its costing a fortune, I'm literally broke now.
Oh, okay - didn't realise you'd already purchased it.
In that case, I would send both applications in the same package, and include the one shipping label you have already purchased.
If it turns out that you actually need to include 2 shipping labels, UKVI should contact you to ask for another one. If not, then you haven't spent extra money on it.
I kept the supporting documents with me because I was told to send the package from the UK and then I'm being told I should send supporting documents and passports separate (Passports/biometrics from US). I've been told by Lara on here that would be crazy. They will just take weeks to match the two deliveries up.
Yes, sending in one package has always been the case in the past - UKVI have always advised that documents from the same family should be sent in the same package: 1) because they share documents, and 2) because the financial requirement that must be met increases depending on how many people in the family are applying
VFS is very frustrating at the moment because it seems the rules for shipping change every 5 minutes. This whole 'separate labels' thing has only appeared in the last few weeks, out of nowhere... so I really don't know what the 'correct' way to do it is anymore.