1. Long gun.
My choice would be a quality AR (BCM) 16-inch barrel with a mid-length gas system. I would run it with the same setup I always use. Sporting an Aimpoint with iron backups. The Aimpoint over Eotech due to battery life. Much less to worry about with an always on optic with a year battery life. A forward mounted hi output light and a smaller low output light for navigation and low signature.

The main reason is I am familiar with them and I can work one exhausted and mostly asleep. I have used and trained with them literally for decades. Caliber is adequate (barely) and I can defend or take game, and have reasonable capacity. Plus ammo is pretty easy to find.

2. Handgun.
A full sized Glock probably a G-22 with a WML Surefire 300. Again it's a matter of familiarity. I have carried a Glock of one flavor or another for decades. With a G-22 you can carry a 9mm barrel and mags and also use 9mm ammo if you have it. So it is fairly adaptable without adding much weight.

3. I would probably throw in a 22 pistol, a Ruger 22/45 as a pack gun. A suppressor would fit in nicely with this setup. Assuming that I would have to carry all three guns and ammo another long gun just seems to add too much to the ounces = pounds. Pounds = pain equation. I think a Ruger take down would be better, but weight wins it for me on this front.