first off we need some background information, first off have you ever flown RC before.
you said you were new so I will assume not.
if you try to fly the mustang as your first you will almost definetly end up with a pile of sticks at the end of a very short flight.
it would be best for you to aquire a trainer type plane (most recomend a .40 size) and restore this plane as you leanr how to fly.
as for the engine a 54" wingspan it sounds like a lazy tiger. found
here
and says a 20-30 engine any .30 size engine should be fine for the plane.
the parts list is
here
and mentions 2 1/2" wheels.
it says 5 servos I would assume standard servos, but I am not sure.
acording to
here standard size is 1.6X.8X1.4. if this seems about right then yes it is standard servos if not use the chart to find a good match.
if this is indeed the lazy tiger then it should make a good second airplane so if you have flight expirience it should be no problem, but if not I would again recomend getting a trainer and finding an instructor to teach you how to fly.
right before I posted you posted the pic.... yup that looks like a lazy tiger.