Harry, if I'm following you correctly, you're saying that the fore end that came with the new set of barrels goes on, and the latch is partially engaged, but not flush? Then I'm assuming the unhooking pin is fully pushed back in.
Even if the unhooking pin were only partially compressed, the cocking hook should stay engaged.
I think I'd still like to see the extractor stop screw removed to see if it cocks, but you could just remove metal from the underside of the barrel lug to let the tumbler fully engage the lug. This wouldn't be my first choice, since removing metal is hard to undo.

Edgar, could you please explain that procedure to me like I was a 5 year old?

I seriously don't understand what you're saying.

I don't know how to add text to photos, but my little sketch should work.
The little arrow is pointing at the tip of the underside of the Fore end lug. If the tumbler, in the FE latch is engaging the lug, but not fully closing, using a diamond file, start at the tip, and keep the angle (dash line) as close as possible. I have a 3M product emery paper with an adhesive back which i put on the edge of a ground flat stock bar. Don't use a bastard file, or you will quickly have a loose fore end.

I will say, this is how I have gotten a fore end to fit, when I've fitted a set of barrels not done at the factory. It isn't intended to 'adjust' an existing, matching fore end. The process of fitting another barrel to a gun is complicated, and the fore end fitting can be as tedious as the barrel fitting. Ive screwed this up more than once, and it can be a major sweaty palm process. I've got 60+ years experience and have had some go on before dinner, and others only after weeks of cursing. The reward is almost never gotten without risks. Also, I only get involved with these projects on stuff I own, and won't touch anyone else's gun.

Edgar,

The forend that came with the barrels I'm trying to fit snaps on, but the gun won't cock.

The original forend to the gun will allow me to cock the gun with the new barrels.

I was hoping the forend to the new barrels would allow the gun to cock, but that is a no go at this point.

My next step is to remove the wood from the iron to see if their is anything glaringly obvious.

I do appreciate the help.
Thanks,
Harry

I think I would quit there, and call it a day.