I have used the Primos trigger stick (Tall) for three years, and like it very much. It takes some time to get used to the hold and balance but works well for my F/T needs.
LOL not a bullpup for sure! Even with the airforce lss setup it's still like pointing a javelin :D I have gotten used to shooting it from my trigger stick, but no go for real brushy Dence cover.
As a lefty I have had to adapt to a right-handed world. That said, I'm more comfortable shooting a rifle left-handed, with the cocking lever on the right side.
Welcome to AGN. The BRK pathfinder is a great choice. L.Leon's posts about the BRK rifles are well-known and respected. You can learn A-lot from his experience give them a read.
I can't attest to the Ronin on the red panda, but it does a good job on the Texan .457 I have. It also has an extension available that I think is 6" long by the same diameter as the Ronin to help with the noise. The downside is 12" of extra length :(
Welcome to AGN. with the request of interchangeable barrels aside, I would go for the Brocock sniper xr in .22 cal and a odb/donny fl sumo moderator. The jsb 15.89grain will give you good results in the accuracy dept.
Welcome to AGN I enjoy shooting with my grandkids as well. There is plenty of target range ideas, as well as a great supply of printable targets here on the forum, that you can print out and shoot.