Question Fitting 3 seats in a Prius V (and if that doesn't work, Subaru Outback)

We're adding a third baby to the family this spring and wondering about success with fitting three across in the Prius V. It looks less than ideal, but we already have a few narrow seats and I'm hoping it might work. We currently have a VW rabbit with two seats in the back, and hoping to keep things gas efficient and moving on to a Prius. We also have a VW Eurovan for those times when we need space, and we'd likely trade that in for something more reliable like an Odyssey, should we be needing that space on a regular basis. We're also considering a Subaru Outback, not as great with the gas mileage, but more spacious it sounds like. We do a lot of driving unfortunately, so for our everyday trips 3 in one row in a gas efficient car is really appealing. Also looking at the Honda Accord Hybrid, but it's very difficult to find one used. (for the prius v and outback we're looking at 2013-2015 models).

I have a 6 and a half year old who is in a high back Clek Oobr (and we have a Cybex X-fit booster for her in our van); my 4 year old son is in a Clek Foonf, he's currently FF, but happy to move him back to rear for better fit, he was getting no AC in the summer and would be sweating and read in the face, so we moved him to FF sooner than needed. He also has a cosco highback 2 in 1 seat. We have a second Foonf that used to be my daughters, she's now too tall to fit in it, but I would be happy to use it for baby #3 with the infant insert if it fits. I'm also fine replacing these car seats or finding the right infant seat for the car. I am not terribly concerned about a dedicated infant seat as I prefer just to baby wear. Also, my son was huge and was too big for his infant seat at 8 months (and we moved my daughter to a Coccoro around the same time - we no longer have that seat however).

We're planning to test drive and see what what we can puzzle together, but any advice or ideas of alternative seats we might try would be greatly appreciated.

We tested this in both of these cars (2015 model years) when we were car shopping a few years ago. It is doable although tight in the Prius V, and infinitely easier in the Outback (which is a wider backseat--one thing that surprised me about the Prius V when we got into the nitty gritty of the dimensions was that, though I perceive it a bigger than the standard Prius, it's only a couple of inches different in the backseat). We were able to fit the three seats we had at the time--Britax Marathon G3, Cybex Aton, and Combi Coccoro--into the Prius V, though. The only thing I remember being tricky was something about the buckle stalks (but don't remember details unfortunately). The seats you have should work a little better since the Marathon is pretty wide. The Outback was easy peasy.

I will say we got a smaller Subaru and our biggest regret is the abysmal mileage (well below EPA mileage); often wish we'd gone with the Prius V. YMMV (ha...) depending on how/where you drive, though. (We do a lot of city driving with short trips, and don't use the AWD enough to make it worth having.)