1. Not speculating. Manga facts aren't speculation.
2. The Hiraishin User can teleport to or teleport something after the chakra link or a physical contact is formed.
3. Susanoo can't evaporate at FTG's speed and that's clear as a day. We've already seen it many times that it takes time for a Susanoo to evaporate, can't be compared with FTG's speed which technically [it's a space time ninjutsu] is greater than speed of light. This right here is a non-refutable thing. Also Susanoo is nothing but users chakra which can be used by the Hiraishin users against Susanoo User to form the said chakra link and deal with it by 4 ways I had listed.
4. Madara himself put Tobirama on his level. Also I think that Naruto posses a larger chakra pool than Madara. His father Minato is a perfect Sage as senn even though he's not as skilled as Naruto but the fact remains that he has achieved a perfect sage mode, now what do we know of perfect SM?
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Minato's better than Tobirama who is on EMS Madara's level [said by Madara himself]
4.2 If that's so then Minato 1-shots Madara with sound genjutsu because Sound Genjutsu bypasses even the Susanoo and doesn't affect the user or SM user which Minato is [thanks to Ma and Pa] and Madara isn't.
Two can play the Genjutsu game. Minato falls to visual genjutsu by you, then Madara gets 1-shotted by sound Genjutsu.
Hope you can still dance.