I think you will be fine.
Some softer emulsion films like Efke or maybe Foma?? can reticulate if shocked too much.
Also if you used a fixer with hardener that will help 'toughen" the emulsion.
Nothing past the developer stage will affect grain, though reticulation will produce a grainy sort of look.
A 10 -15 temperature drop is a lot, but probably won't be a problem for Kodak products as Bruce said.