Britax Frontier 85 or Parkway?

Bit of backstory:

We have 2 vehicles, 3 kids, 6 Britax car seats. Our car (most used) has 3 Frontier 85 car seats in it. Our SUV (seldom used) has 2 Regents and a Decathalon in it. SUV was just in an accident and we need to replace those car seats (which are all discontinued now so looking between Frontier & Parkway).

DD is 6 and will be getting the Frontier 85. Not sure if I should get the SICT or not. Opinions?

Boys are 8 and 10. Used to riding in 5 point harnesses. Very seldom have they ridden using a belt positioning harness. 10 year old is very small for his age (think below 3rd percentile for height, 25th for weight). 8 year old is bigger than him. I want to say my 8 year old is 52" and my 10 year old is 49.5? I really need to check though - been a while.

I'm toying with getting Parkways so that way when they outgrow the Frontier's we have in our main vehicle, we can switch them over - but in the meantime when we do drive our SUV I want them to have super safe seats since we drive in the Los Angeles area with a bunch of fool drivers, and SUVs tend to roll in accidents...

What would you do in this position?

I'd probably buy all three boosters of any brand they liked. They all have six, eight, and 10 year old skeletons, so they're perfectly safe in boosters. And all carseats pass the same testing, so Britax isn't necessarily best. They just have good marketing.

Did the accident meet the criteria for replacement? Britax allows for minor crashes.

Wendy