I do not have any certain chemical infos on Gorilla branded glues.
One thing is sure: both the Blue (and Pink) and white foams are chemically polystyrene material. The colored ones are extruded (fully homogeneous) and the white one is expanded (i.e. from "grains" or "pellets" expanded (puffed) up to fill the plain, or shaped mold.
All solvents and thinners are harmful for polystyrene, and cyano, as well. Alcohols and water is exception.
Epoxies without thinner are not harmful. So I suggest for general use 5 min clear epoxy glue, for foams. Maybe 20 min ones for bigger, complicated surfaces.
There is some special kind of cyano, for polystyrene, but I do not know its brand. It is easily find on specialized pages, or shops.
There is some not-too-hard siliconrubber based glue (in Europe:Pattex Total), easy to cut after drying.
The vinegar-smelled water based white tablemaker glue is affordable, too, but bigger surfaces need several hours for dryig. (polystyrene foam is tooo hermetic for humidity...)
Istvan
Remark: recent years appeared a new kind of white foam in modelling: EPP (extruded polypropylene foam), it is absolute resistant of every glues, resins, paints and solvents/thinners. Sorrowfully it is far more expensiver than XPS, and the elementary structure is 5-10 times rougher than XPS...