Gluing parts together under tension is obviously not desirable, however the experiments
I made looked promising.
My main concern is will it last over time?
Filling the space will lead to a badly fitting wing.

When dry-fitting the fuselage of my 1/32 Pacific coast spitfire, properly joined on top, the bottom length shows an opening of 3/16", gradually becoming fully joined at its full length.

The tension required to join the entire seam is moderate, a strip of tape holds it together easily.

I've experimented on scrap using Tamiya Cement and it held quite well.

I also tried some Green Putty which also held up well.

My thought is to tape the seam. Cement the entire length. let it dry.

Cement the seam from the interior (it is mostly reachable). Let it dry.

Finish by spreading green putty on inside of seam. Remove tape.

Any suggestions?

If you're concerned about the warped parts pulling apart, then the solution is to make use of the properties of thermoplastic. Heat the parts and then allow them to cool while being held against a board. The best way to do this is to find a straight board larger than your part and devise a way of holding the part firmly against the board. Dip the part into just-boiled water for a few seconds to warm it and soften it slightly, then take it out and quickly fasten it to the board so it's held against the straight surface. Allow it to cool and set into its new shape. Be very careful not to squash it while you're doing this.

Good technique but not in this case.
The cockpit is installed which would fall apart under
the heat.

Okay, then glue the fuselage with large styrene tabs on the lower part. Once glued and wrapped firmly with rubber bands and clamps, flood in some liquid cement from the wing cutout to melt the tabs in place. Then let it set overnight. You could even pour in some 5 minute epoxy afterwards to help re-enforce the join. Make a dam at the wing cutout to help hold the epoxy in place.