I have a tiny 24-pound DD rear-facing in a britax advocate in the second row captains chair, a new baby coming in November who will be in a Chico keyfit probably, in the other captains chair second row, and my older two (DS is almost 5, 45', 50 pounds in a britax frontier 85 SICT, and DD who is 47' and about 48 pounds, but will be 7 in July, also in a frontier 85). I planned to harness them both to 85 pounds, but with this stupid one anchor thing, I can't have them both in the back, which makes the most sense convenience wise. Is it ok to transition the 7-year old to a parkway or other high back poster, and keep the 5-year old in the frontier when baby comes in November? She will be 7 years, 4 months and is pretty mature doesn't really fall asleep in the car, etc. for some reason I am feeling guilty about this!
I can't really help you! but I saw your post and where you are from (we are in Easton) and just the other day ordered a new car, we had been in a company car program for 15+ years and only one kid to deal with (still in at 5 a car seat with harness with a car seat made to use in what we were in) - we have never had to deal with insurance because of the program we were in, anyway, we now have private insurance and they suggested we go to the state police with out new one and make sure it's all secure but also they would be really go to ask questions to as well - they might help you?? just a thought, as we were told, that are suppose to do it! not what you might have wanted to hear but they could give you some suggestions - just a thought- good luck
There is no known safety advantage to continued harnessing once the child is mature enough to sit safely in a booster. For most children that happens from 5.5-6, so I would have no problem with boostering a 7 year old. Most kids also won't fit in the harness until 85 pounds anyway--- they'll outgrow it by height before then.