All right.
Since from, what I know, Hyrule Warriors is about Lana and Cia dealing with a screw-up in the timeline (We know, Cia being Yandere for mah boi and such).
But there's so much going on Hyrule (Including things like "civil wars" and such), and with the focus of your proposal being centered towards OCs, the entire realm can be an alternate universe which Skyward Sword - and following that, the entire "hero of time" ordeal never happened. With that, Link would either be a non-existant concept or else a legendary superhero.
Zelda's storylines are very much straightforward, with Link goes to town, whacks Ganon, saves Zelda, the end. Even with the "Dynasty" aspect, things still kept like that. With OCs being the focus of the scenario, things will need a bigger approach. In other words, this will need a bigger threat than Ganondorf/Demise, and even bigger than Cia willing to jump in Link's trousers.
Again, going back to the AU idea: Hyrule can be a place where everything that could go wrong, went wrong. Without epic villains behind the curtains, what could happen? Who could be the responsible, for example, in a civil war between Zoras and Gorons? Or else, Sheikah being discredited as royal family protectors because of rumors regarding high-rank members, or else belonging to a secret society of pariahs, like "the weird assassins with demonic red eyes"...
In Dynasty Warriors they take a lot of liberties with the source material (Ditto, going to extremes with their crossover, Warriors Orochi). Hyrule warriors did the same with a certain degree. I don't expect things here to be crazy and complex like Warhammer 40k, but seeing how the focus of this proposal is within the OCs then stuff can be really neat to work with.