At this point I believe that it is pretty clear to anyone that knew Mongoose that Mongoose is no longer Mongoose. So mongoose can be our official Human form if we want. Or we could grab and attractive-looking beggar, hope it isn't a monarch/god/mage/god-mage-monarch in disguise, and just declare them to be us in all official engagements...
As for the immediate term, we are on bed-rest. We can tighten our defences, but that might tip our hand. Let's just get the death-rot pipe-line established and build up a stockpile inside the city before we start selling it. I should like to send some cultists to get into contact with the local farmers and try to get some of them on-side to train and assist the goblins, who should start fencing off some flat, fertile land for fields and build roads to it. Ideally the goblins will avoid slaughtering any farmsteads while doing so. I would hope that farmers have been avoiding goblin lands.
I want to talk to the necromancer about their craft. We should know what sort of maintenance costs are involved in undead, what their capacities are, how they fail(What happens if their tolerances fail, for example, if we end up with more of them than we can maintain.), what the difference between an adept and novice necromancer is, and how easy it is to acquire new necromancers.
I should like it if the Priestess were to tend to us, we could use a bodyguard and a priest really should have some means to help their injured god. If we get devour of course, then we can likely heal lickedy-squick regardless.
I would also like to send a couple of cultists into town with some coin and have them evaluate the local tradesmen to see who is likely to be willing to work with us and where the good deals are. If they pose as adventurers then they should be able to purchase most of the commodities that we are interested in without appearing too suspicious.
That seems to be spreading out forces out thin enough, perhaps sending out some goblins to scout the surrounds would be good though, it would be nice to know if there are any useful cave-systems about or if there is anyone living nearby. And try to get a run-down on goblin needs, are they carnivorous? Do they operate poorly at night? Can they work their own smithies?
P.S.
I would still prefer something completely non-human, but a human skin hiding a writhing mass of snakes is not entirely offensive... There are also fantastic civilians, we could do the same thing with dwarves or elves or goblins or possibly even stuff like fey or well, if you really want to confuse folk, go for something else that practises possession, do they have ghosts here? What about blood golems?