As you say Karloff, Pandie Plat is apparently dominant to E&S, therefore those E&S boxes can only be hiding E&S or more recessive as a hidden fur can in fact never be more dominant than the shown, always same or more recessive, so to use only if there is trait interest i think, as the fact of there being Pandie in background will not help.
You don't say though if Lox is showing or hiding the tail you want, if he isn't then it could be a better idea to use the 8T male showing it, one step surer once you manage the pan die.
If he is then Lox and Gretel should eventually give Gretel's shown fur you just have to keep trying and hope for a boy so you can breed back.
It would of course be easier to advise the best course of action if we could see the pedigrees.
Of course if you wanted E&S they'd be giving you Pandie all the time (
), and in fact the odds favor the shown dominant passing rather than hidden recessive.
Hope all this makes sense and good luck.
