Not to be much of a downer but the whole idea of creating a viable third party is a futile pursuit, now that corporations have the same rights as human beings and money can be defined as free speech.
Essentially, our nation is a modern corporate oligarchy and our federal elections are the world's most elaborate public relations stunt. A whole entire industry has been built up around it that generate billions of dollars for both the RNC and DNC and their subsidiaries, not to mention wheelbarrows full of cash that are funneled into the mainstream media, major lobbying firms, advertising agencies, consulting businesses, and marketing conglomerates.
On top of that you have the present electoral college and Senate constructs effectively destroying the legitimacy of the popular vote.
And what's more, underneath it all, you have a vast web of deception and trickery in the form of gerrymandering, various forms of voter suppression and manipulation and nebulous, numerous partisan registration laws.
If a third party is successfully added into that mess, it will just become another wheel in the machine.
What is needed is a near-future political "Gamestop" moment in which Millenials, GenZs, iKids, etc. use social media and successfully game the system to create a viable candidate to run outside of any party affiliation and who with garner millions of votes outside of the techno-totalitarian frameworks noted above.