In the absence of current, aluminum self protects by creating a hard protective coating of aluminum oxide when cut or exposed to air. Repeated erosion of the aluminum oxide on sheet metal should be avoided.
My understanding is the turnbuckles from the factory are aluminum and they are in contact with steel eyebolts. I see no failure occurring after 6+ years of heavy use.
Many 1,000,000's vehicles have aluminum heads bolted to steel blocks with steel bolts with no galvanizing.
That reminds me about the turnbuckles. Mine are actually steel hooks and AL turnbuckle body. And as I've posted ad nauseaum, I'm still using the FWC originals almost 22 years later. Never seen any corrosion in the contacting thread areas but then gain, they are used only seasonally.
Having a AL camper deck I have seen a white powder which assumed was aluminum oxide, mostly wherever there has been a hole drilled (and not repainted). Seems particularly bad when a SS fastener is used in the hole. These SS fasteners are always thru bolted as the I believe the threads in the AL would never stand up long term. This corrosion might be aggravated by weather exposure.
The bare AL deck has cargo tie downs that are plated (zinc ? but smooth). These are thru bolted with a similarly plated fastener. I haven't seen any corrosion here but even if, the backer plates are 1/4 AL and frankly, will prob outlast me.
Back to the OP. I read it differently. Less that the poster was looking for mounting solutions and more that he/she was cancelling the order, pointing out the concern to the readership and hoping that the mfr would understand.
I had a few thoughts on cancellation or immediate resale which, if the OP is interested I can post up.