A simple kit 'bash' like that certainly is possible and makes a lot of sense. Exchanging the built up surfaces for solid ones will allow less or no nose weight (a situation common to a lot of trainers particularly ARF's).

Strength of course is always a consideration but with two similar aircraft for the same mission and the areas of the fixed as well as the control surfaces are close there should be no issues. You will probably end up with a lighter and better flying airplane. Look at the airplane in my Avitar, it is a Kaydet Senior 'trainer'. I also have a forty size Aerostar trainer that flies nicely with no horizontal tail or elevator at all!

Kit bashing 'The Lost Art'

John