Galvanic action on gold plated PCB
Galvanic series is entirely dependent on being immersed in water, mostly sea water. It has no bearing on much of anything else.

IF you were to take into account anything what-so-ever then I would take into account corrosion. It is true that some metals don't play well together. That really isn't the case here because these metals are all layered so that you don't have to worry about that. Resistivity is of no consequence here since the resistance added by either HASL or ENIG is extremely small either way. To be honest, your solder would add more resistance than either of these processes would. mKeith is correct and the only reason you pick one over the other is a cost/benefit analysis where you take into account that ENIG will keep a board's contacts free of detrimental oxides longer than HASL would. This improves solderability.