You should be fine with the AEV 3.5" lift. The ride will be much better. This is because the new springs are much stiffer than the stock, that means not only will it still look nice with the new bumpers, but it will also make sure you don't get any wobbles. Also I'm not sure what the exact kit you are getting is, but you should definitely get a heavy duty steering stabilizer, adjustable front track-bar, and rear track-bar relocation brackets. As far as the tires go, I have heard nothing but god reviews about the mickey thompsons, I have bfg km2 FYI and they are fantastic.
Re-gearing. That is where you change the gear ratio in your differentials. What happens when you increase tire size is that the circumference increases too. Going from 32's to 35's makes the circumference increase by 10%. This means that for every rotation of your axle, you are traveling 10% further than with the old tires. This means that the engine will be putting out fewer RPM's to go the same speed as before. This means that the engine will have to work harder to push out those RPM's. So when you re-gear, you increse the gear ration so that the engine puts out more RPM's to turn the axle once. It will give you a little more power. I don't know what type of gears you have, but if you have 3.21 I would re-gear definitely, but if you have 3.73 you don't have to but may still want to. It also has to do with the type of transmission you have. If you have a manual, your best ratio would be 4.56 and if you have an automatic, your best ration would be 5.38. Her's the link so you can check it out. http://i149.photobucket.com/albums/s.../JKgearing.jpg