1) No I don't inhale, but I do retro-hale quite a bit (same goes with cigars). Draw the smoke into your mouth, and exhale through the nose. You'll draw more nic that way, if that's what you're after, and IMO enhances your experience of the tobacco. Especially with blends containing perique.
2) When I smoked briars, I only kept separate pipes for blends containing latakia. For cobs and clays, I don't dedicate to anything.
3) Yes mason jars are good. If I open a big (8 oz or 1 lb) container, I immediately store it in a large mason jar, and transfer a smaller amount to a small mason jar for near-term smoking. The smaller tins (2 oz), I just leave it in the tin -- it's fine for a long time.
4) I've only ever used butanes (bics or pipe lighters). I can't attest as to whether there is some advantage using matches, though many folks will tell you it helps prevent charring your pipe (if you're not careful with your lighter). Again I only smoke cobs and clays so this is not relevant to me.
Enjoy, and welcome to the forums!