Hi Aleco,
1. You'd probably get away with running a 33" tyre without changing your gear ratios,
but you're asking for trouble and the TJ is not gonna be much fun to drive - especially when towing.
Realistically a 31" tyre should be fine on the standard ratio (towing won't be fun, but it never is in a TJ). You might notice a little difference, but others will tell you it's better
2. No need for an SYE with that size lift as you could probably get away with transfer case spacers (probably included in the lift you get - assuming you get a complete kit). Any higher than 2 inches, the size of the transfer case spacers is going to increase and slowly remove any benefit of your lift (i.e. the belly of the TJ is going to be hanging down), making the SYE a better option with higher lifts.
Hope that helps!