Having a nightmare getting 3 across in my 2012 Honda CRV. I’m looking for a recommendation for 3 different seats that will work together. I’m familiar with the lists of 3 seats that work together, BUT the catch is that we have a HB belt positioning booster which isn’t addressed.

1 HB belt positioning booster

1 infant seat (preferably Chicco Keyfit if possible since 2 Grandmas will be caring for the baby and also another baby that will be in a Chicco Keyfit on alternate days so we would like to be able to use the same base), and then eventually a RF seat. If it makes more sense to just invest in a specific very narrow RF car seat like a Clek and skip the bucket seat to save money in the long run, we will do that. We will only use the bucket seat for about 5 months anyway because myself, my mom, and my MIL have all had upper arm injuries.

1 FF harnessed seat (she will be 4 when baby is born)

We already have:
Diono Radian (RF or FF)
Graco Tranzitions (FF only)
EvenFlo Big Kid (narrowest booster I could find)