If you want to use the wheels from your Allez on your new Surly you should probably get the Cross Check. The LHT is spaced for 135mm (MTB size) rear hubs. CC is spaced halfway between road and MTB hubs, meant to use either or both.

Is your front derailleur clamp-on or braze-on? If clamp-on, do you know the clamp diameter?

The rest of your drivetrain should be able to get moved over to the new frame, I think.

You will probably need to get new brakes. Cross Check is meant to take cantilever or V brakes. Keep in mind that your brake levers need to be compatible with the brakes you choose (or vise versa).