He has a thing for oddball calibers. Now, I myself have nothing to brag on in that department, seeing as how I have a couple of Lee Enfields in .303 British, a .455 Webley revolver, a Webley in .38 Smith (NOT .38 special) and a .41 mag. BUT, oddball calibers are not good for first guns because ammo is expensive and not readily available.
I would stick to 12 ga., .308 Win (7.62 NATO), .22 rimfire, and .38/.357 Magnum because if ANY ammo is available, those will be. (I am personally prejudiced against 9mm, and I prefer .45 ACP to the .38, but again not for a first gun.)
Everybody should begin with a .22 rifle (not a .22 magnum - talk about difficult finding ammo!). Ammo is available everywhere and dirt cheap, zero recoil, ample accuracy with the right selection. I wouldn't bother with a bolt action though, if you need discipline in placing your shots just load one at a time. I am very happy with my Ruger 10/22 Stainless, although the rotary magazines are a bit fiddly (I would buy a couple of spares).
A reliable .308 rifle is a good thing to have, my hubby swears by the FN-FAL but I find it too heavy and bulky to tote around. I have a little Ruger M-77 with a 4x Leupold scope on top, and it does everything I need for it to do. Probably a semi-auto would be better than a bolt action, but the M-77 has a very smooth and quick operating action. I love my Ruger and I can drive tacks with it all day long.
A good pump shotgun is the best first shotgun. Our hunting club has eight Remington 870s that we use day in and day out in training and during hunt tests. Some of them are older than I am . . . they get battered around and treated pretty roughly, but they remain reliable and accurate.
I agree with a .357 because you can feed it .38 sp for practice, but a six inch barrel is going to be very awkward for a new shooter. Four inch to me is a better compromise between recoil and ease of handling. Once this shooter gets comfortable with a revolver, he ought to look into the 1911A1.
Just my 