I played ja2 quite a bit in the past and loved it. I was thinking of giving the first game a chance and due to my success with melee in the 2nd, i would like to try it in the first. A couple questions:

1-Who would you recommend that is good at melee?

2-Does dexterity have any effect on melee or is it based mostly on experience?

I am not quite sure, but my experience is that higher marksmanship helps, at least when using a chain saw.

There is no real mellee in JA1. You can use combat knives to deal damage. Normal black knives deal little or no damage (though they do reduce energy)... There are no chainsaws that I know of...
But this type of combat is used extremely rarely. Mostly it's guns only.

Not sure what affects the knife fighting skills...

(^^ The above is about JA1 without any expansion packs. It might have been changed in deadly games).

Except for knives you can throw rocks if I remember correctly.
The only reason I used knives in JA1 was for mercs who needed to swim.
The knives gave them a good chance to survive the water snakes.