Thanks to all for the suggestions and confirmation.
As it turns out, my wife is not crazy about the gathering model in this game, she's more of a *gather things as her main is adventuring* type and doesn't particularly enjoy dedicating time to it. So she will remain a BRD only while I take on BOT, MIN and FSH, along with CUL. My main motivation is not so much the profits, since in every MMO we've ever played, entering the market after the game's been out for years is almost never profit-viable. I'm more interested in making my own buffs for the two of us, and the fun of it.
But I do do see how leveling each craft up to 15 is easy, my 3 DoL skills are all already 20+ and we just started playing (our mains are only just now hitting 40). I'll probably do the cross-craft skills thing in order to enhance the experience. The only downside I see is having to maintain so many different gear sets!
Thanks everyone, and I do appreciate any other tips or suggestions!