It is actually easy to put a carseat in the Plus One seat. I know many car seat safety technicians who say it is fine.
What car seat do you want to put in the middle forward facing? The Plus One seat does not have a top tether anchor and many seats require the use of one, so my preference would be to put the rear-facing baby in the middle instead. I have had 3 carseats installed this way in my '06 Ody - Britax Boulevard FF, True Fit RF, Britax Roundabout FF. Was very, very easy to do. Good to know if I ever needed the cargo space in the back I could do it with my 3....but my favorite thing about the minivan is that they are unable to TOUCH each other!!

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