Idessa: You can make diplomacy or bluff checks whenever you have a group of items figured out and a buyer to attract. Senenmerek says "I am the Captain of the Guard not your wife, do your own writing, priest of the dead god". OOC he's not going to create anything that you can sell to make money, and he has noticed your Pharasmin symbol. He's not opposed to Pharasma, but he only takes orders from Nethesian followers. I'll stick with what I told TC, if you spend 10gp per item group on little things to increase the presentation, I'll give the buyers a -2 to sense motive or appraise (which attempts to counter your diplomacy/bluff).
You do find a merchant that mentions selling supplies to the Scorched Hand "I sold them food and clothing, for a trip it seems. I'd wager they've already set out into the desert." For the invisible man you only get "Invisible you say? No, I haven't seen anybody matching that description" and some odd looks.
It's going to take me a while to figure out prices on everything you're selling, I'll have it ready by tonight though.