definitely devinycell. by far the best option of those you mentioned. get is as close to the inside contours as possible, but without any high spots. you won't be able to close the mold properly, if the core is to big. then get some micro balloons, fill up some resin with it, until you get a viscosity between modelling clay and cake dough. make an even layer on your parts (key them from the inside, or use peel ply) place the core inside, and close the mold. you could laminate the seam area on the core with some layers on biaxial carbon before, to improve the joint. or you could laminate the plys into one part, with some overlap, then add a layer of "bonding putty", place the core inside, then cover the second core half with bonding putty, fold the overlap onto your core, and close the mold.
the second option might be structural better, the first one easier to perform.

as the middle of the profile (where your 2 parts come together) will be the location of the highest shear forces, you should definitely add some layers of carbon there. ideally at 45° fibre angle.
if you are planning to fill the whole wing with a core, then soric, at least in my opinion, might not be the best choice. simply because it is not very light. and it might be difficult to get it into a shape, wich really suits you needs.
if you want to try it with soric, you could also not infuse the halves separately,  but leave one with an overlap at the flanges,  place your soric (accurately shaped) core in it, lay the overlap over the core, and place the second half on top, seal the mold, and infuse everything in one step.
you really only want to use soric, if you either need the flow propertys, or the drapability, or both.
for your process, I would recommend a solid foam, and microballon filled resin to bond it.

(Relocated from Resin Infusion)

'm planning to create a 2 part mould for a wing like design (a hydrofoil mast). My plan is to infuse each side separately, trim the flanges, and then join the 2 parts on molds with compression, using a core material (and maybe a few layers of carbon). Could this method work? And if so, as the cavity between molds will have some of the surface shape, is Soric XF a good choice for core material (i'm afraid of the pressure stable characteristic of soric)?

Thanks!