Knit jackets in the 3rd TBB drop, very nice. Expedition jacket looks great. I think I have shot my bolt for this season on the shawl collar knit though.
Also, "Boumemouth" shirt? I can't tell if that's a deliberate misspelling or someone's seen "Bournemouth" with a handwritten "r" & "n" run together.
I think J Crew carry Dept B, or you might be able to find Barbour SL somewhere which is also a slimmer fit. Otherwise I'm not sure what there is in the US - I would guess Filson might do a similar waxed jacket or you might like one of the options at Epaulet.
Traditional Barbour jackets are fairly loose in fit, but I think the newer Dept B or xTokihito stuff is slimmer fitting.That looks like a moto style leather, which to me are some of the most minimal looking leather jackets - the biker style you're thinking of is probably the double rider. I have no experience with Boss in any capacity but I suspect you would be paying a large premium for the label, whether that is good or bad is up to you.Don't know what quality/price...
There's quite a few decent-looking sweats around at the moment. Joe McCoy's maybe, if you want an old school repro. EPLA are doing hoodies too if you want something less rigorously heritage.
My gym bag is by Briefing, US-made, heavy-duty nylon, I think they make for the military so it's fairly hefty stuff.
 quick check, it's the "gym wire bag"