With a newborn and airplane travel, you'll want to start out with an infant seat... easier to move around and travel with and fit newborns much better than convertible seats.
Out of the three I originally listed, the Snugride is generally easy to use and what I would consider to be a budget option if money is tight.
The Graco SafeSeat1 and the Chicco Keyfit both have built-in lock-offs, which means you do not have to mess with locking clips or locking your vehicle seatbelts.
The advantage to this (sorry, long explanation)...
Your vehicles have switchable retractors. When you pull the seatbelt all the way out, it switches to (ALR) locking mode. You will hear a clicking noise as the seatbelt goes back into the retractor and if you try to pull it back out again, it will not come (until it's retracted all the way back in - which switches it back to unlocked/ELR mode).
The disadvantage to the switchable seatbelts when you have a rear facing seat happens when you go over bumps, the seatbelt tends to slowly retract itself a little more and more and eventually the shoulder portion is pulling up on one side of the rear facing child restraint and causing it to lean to one side.
This is not dangerous, but after awhile the seat needs to be re-installed to level again and it just tends to be slightly annoying.
The built-in lock-offs mean you do not lock your seatbelt and there is no tilt factor to worry about.
Of course, this could be a moot point because all of your vehicles have LATCH/UAS and if the child restraint is installed in an outboard position, you can use LATCH/UAS and completely avoid the seatbelt all together.
You can not use LATCH/UAS in the center position to install because you would be borrowing anchors from the outboard positions and this is not allowed per your vehicle manufacturers. If you install in the center position you'll need to use seatbelt. The Rav4 has a bit of a wonky set up in that center position (due to the seatbelt being offset into the driver's outboard position), so I'm not positive that a seat will install nicely in the center position... you may need to install outboard regardless.
The Peg is generally forgotten about soley due to it's price point. It is a very nice seat though and if it's one you like, then by all means go ahead and purchase it. It fits small babies very well and is a nice cushy seat. A good friend of mine owns one and came home with her daughter just barely at 5lbs fitting beautifully.
The Pegs also only used to be allowed/able to be installed with the base, which gave it a huge disadvantage if you ever wanted to install it in a secondary vehicle without pulling the base out of the primary vehicle. This is no longer an issue as they are allowed/able to be installed without the base.
The Chicco is brand new to our market, so even though it's price point is high, it's still got enough other features that make it worth that price (to some).
Most kids will fit in the Peg and the Chicco until somewhere between 10 months - 13 months old. After that you'll need a convertible to continue rear facing and then eventually turn forward.
Most kids will fit in the SafeSeat1 until somewhere between 18 months - 2 years old. It's weight limit and height limit allow for longer time in this seat.
We strongly encourage parents to rear face to the limits of their seats and aim for 2 years old as a minimum whenever possible.
There is no wrong choice between the three seats (Peg PV SIP, Graco SS1, Chicco KF). They are all very nice... it just matters which one you like the best and how they install in your vehicle. Head to a store and try them out in your vehicle to see what you think.
