Which would be best?

I'm switching car seats around again. DD#4 has head slump in the nautilus and it hadn't been a problem up until recently. Now she complains that her neck hurts. She still falls asleep quite often in her car seat (almost every afternoon when we go pick the big girls up from school and pretty much any time she's in her seat for more than 15 minutes). If she had her choice, she'd sit in the MR FFing (she's too tall to RF in it any more or RFing in it would be her first choice). DD#5's first choice is RFing in the EFTA (or "comfy black seat" as she calls it). But, I really don't care who is in what seat as long as everyone is safe. Having them in their seat of choice would be a plus though.

I have tether anchors on all three seats on the second row and none in the third row. (2000 Ford Excursion, and I'm pretty sure I can't have any installed for the third row). The only head rest are on the outboard seats in the second row.

Right now I have DD#1 behind the passenger seat in the second row in a nbb (and I really need her there for school drop offs and pick ups. She puts her booster in the floor and lets the kids in the third row in and then they get in first and she can just put it in the seat). DD#5 is in the EFTA RFing in the center of the second row. The seat behind the driver seat in the second row is empty. I could not get the EFTA tight enough without it tipping in the second row behind the driver seat, but I didn't try very hard because it started raining. I could always try a locking clip if needed. In the third row DD#2 and DD#3 are outboard in HBTBs and DD#4 is FFing in a MR in the center. BUT, there is no tether anchor there. I'm not sure if the MR will fit FFing beside the EFTA. I'm thinking its probably not going to work. Does anyone know how the MR tested without the tether? Should I leave her in the nautilus even with the head slump issues (before it started bothering her, that's what we did. But now she's begging to ride in any other seat because she says it hurts her neck..). I guess my main question is, would you be okay with a MR FFing and not tethered? How about the EFTA FFing without a tether (if it would fit between the two TBs, which I don't think would work, but it might...).

Could you RF DD5 in the third row? So that DD4 could have a tether in the second row?

Does the middle seat middle row have a lap/shoulder belt? So if the EFTA didn't fit in the back you could do NBB, HBB, and MyRide across the middle row and EFTA and HBB in back.

There are lap belts only in both center positions. If I RFed DD#5 in the center of the third row I'm not sure if DD#2 would be able to get to her seat (if she'd have enough room to crawl under it). I'll give it a try Once it stops raining (or even slows down so I don't get soaked) I'm going to go out and try some more arrangements. Ideally the MR will fit beside the EFTA in the second row. That leave the two kids in HBBs in the third row and they both have plenty of room to buckle. If that doesn't work I'll try RFing DD#5 in the third row. I really don't want any FFing harnessed seat untethered. I told DH we definitely are going to need a new vehicle before too much longer because we don't have enough headrests or lap and shoulder belts for everyone. DD#2 is on the highest setting on her TB, but I don't want to move her to the other seat with a headrest in a nbb when she outgrows the HBB because I don't want to give up the tether anchor, so she's going to need a HBB with a higher back...

The MR did fit beside the EFTA! So in the center row its DD#1 in a nbb, DD#5 RFing in the EFTA, and DD#4 FFing in the MR and in the third row its DD#2 and DD#3 in HBTBs. Everyone is happy and safe

Woot, woot! Sounds like the perfect solution for you guys for right now. I hope you have no more head slump.