Gate checking Vista V2

Hello, we are travelling internationally with our 18 month old twins and own a used Vista with toddler seat and rumble seat.

Wondering if it's OK to gate check the vista along with the toddler and rumble seats. I know about the UB travel bag, but as we have a used model, the warranty doesn't come into play for us.

I guess I'm wondering a few things:

  1. Can anyone who has gate checked a vista with both Seats before comment on any issues or considerations?
  2. Is a travel bag worth it (UB or more likely Amazon)
  3. Any tips on logistics with twins, vista, 3 large suitcases plus carry on items?
  4. Is the convenience of a travel stroller for the flight worth the inconvenience of having a smaller stroller for a long trip o/s?

TY so much in advance.