I REALLY don't care for this theory, I'm afraid.
Future Guy was stated by Daniels, as being from the 29th Century. He's from even further ahead and ought to know. Earlier factions don't appear to employ time-travel, and get natives of the 22nd Century to do their dirty work. Simply broadcasting themselves back through time, to give schematics for technology that's too advanced or does in fact exist and is just beyond the Suliban/Tholian/whoever it is being aided.
Assuming Archer spends his dotage, thanks to some accidental transport to the far future... how and why would he reward the Suliban with genetic alterations and cloaking technology... that make them such a threat to the 22nd Century?
They killed a whole colony in "Shockwave" and framed it so an Enterprise shuttlepod ignited the atmosphere, with the express purpose of setting humanity's deep space program back. Millions of people wiped out. Decades until Starfleet tried again in all probability. How would Archer have benefitted from that? What's more, why would an older version of the same character, authorise something like that?
A Romulan would be my suggestion. How different would their history be, without pesky humans throwing their weight around the galaxy? A Vulcan-Romulus reunification by 2161, instead of an alliance of that cuts them off permanently from their ancestral brothers. Ultimately given what happened in the last film, they might even still have a homeworld without the Federation around. Or else, Vulcan as the capital planet in their quadrant spanning Empire.
In my opinion, whoever might've turned out to be Future Guy, would have to have been introduced during one of the later, unmade seasons. Probably become deceased quite swiftly, to throw everybody off the scent... Meanwhile the Suliban have been replaced by the Xindi, and then by the Romulans as the main enemy race. Future Guy naturally switches sides by appearing to betray Silik, and giving assistance that enables them to conquer both the Suliban and Tandarans. Bringing the borders of their Empire closer to areas of deep space, the Enterprise NX-01 had already passed by during late Season 1/early Season 2.