Offering potential US co-founder equity in Aussie company?

General question about co-founders, as I have someone in the US I'm thinking of reaching out to - if you are US-based, how would you feel about being a co-founder in an Australian company?

Unless we're chasing VC money in the US, there are a lot of advantages to delaying establishing a US entity as long as possible. The app is already on the App Store via the Australian company and qualified as a Small Business so we have Apple reduced to 15% take for our first $1M. We would lose that if transferred the app to another company, even if wholly-owned.
There are local grant and tax advantages.

Or, to put it another way, given a plan to eventually establish a US corp, especially if the co-founder relationship goes well, would you be OK with an agreement for equity in an entity that's yet to be created (with possible fallback of Aussie equity)?

Context: Touchgram is an established Australian company, first product on the app store still pre-product-market-fit, about to roll out a major new version and then monetisation in the next two months.