Yes, 4.5" backspacing will work fine for those. For PSI, start at 30 or so and work from there. For most accurate PSI, do a chalk test. You can Google for instructions how to do that, or I'm sure kbwwolf will be along shortly to post the links.
As for other things, a procal will allow you to correct the speedo. You will most likely feel the need to regear with the 35s, depending on what your stock gear ratio is. However, if you have a Rubicon with 4.10 gears, it may be semi liveable for a while. If you intend to wheel regularly, I would look into sleeving and gusseting the axle, especially if you have a Sport or Sahara with the D30 front axle. Of course, none of this is anything that must be done immediately, just giving you a heads up on what to expect.
2" body lift! Whoa! You could more than likely have cleared those 35s just fine without the body lift. Not a fan of those on JKs personally.