RFing front to back room Blvd70 vs. Scenera/OnSide Air vs. Tribute V vs. ???

Hi, We're going on a trip with family and the car (a small Lexus 4dr, not sure the model) is going to be packed with 3 adults and 2 kids. One baby is going to be in a SR35 currently installed in the center. DD is going to be the other kid.

We are flying in. I am willing to buy a seat just for the trip if there is one that will work better than what we have (and be easier for the plane etc.) The one I would consider bringing is a Blvd 70. Is there a smaller lightweight seat that will work better and is smaller front to back as she will be outboard? She fits in the Scenera/OnSide Air and Tribute V. I checked last night. I was thinking Avenue, but am worried it is bigger front to back b/c it's taller. How do the BLVD 70, Tribute V and Scenera/ OnSide Air compare front to back? Are there ones I'm missing that would be better? I know that RFing is going to be questioned by family, and it's important enough to me to buy a seat even if it will not last long to ensure she is RFing an not pissing off the person in the passenger/ driver's seat so I don't have to listen to it/ have people gang up and decide to try and move her FFing "just for this one trip." (I am leaving her with family while I attend a conference for a few days, so I want it to just be easy.) I will pass the seat on to someone who needs it when she outgrows it.

What would you do in this situation?

Thank you for your help!

For many reasons, I love the Scenera for travelling. I have never had a problem installing it, but I use LATCH and that may not work in a 3 across situation. I would not want to use a Scenera in a car without locking seatbelts, if at all possible, though since then you need a locking clip which can be a pain. If the car doesn't have locking seatbelts, then dragging the million pound BV along makes sense.

I haven't measured, but both our Scenera 40s and Boulevard 70s fit very compactly--we have installed both in the tiny rear seat of our '07 Forester without any problems. And my dad is able to push & lean his seat way back in his SUV with the Sceneras installed.