I'm sure that the mfgr's don't want to worry about the problems that are associated with the ethanol products....so they strongly suggest that you not use them.
That said, will they work....yes.
Will they last as long as the engines not using the E-85....probably not! Or at the very least, will probably require additional maintenance, which may actually offset any monetary gains from the lower priced fuels. Some of those parts are pretty expensive!!
StaBil does make an ethanol mix, which may be helpful....I've never tried it.