Yeah, I think the problem is that ECI/ETBUS ("engaged in a trade or business in the US") is a very vague concept.
Basically anything happening physically in the US is a potential risk. And then even if they only attribute ECI to the days spent in the US - what is the value of those meetings? An aggressive IRS agent could probably say that, without the meeting, you wouldn't have received that $365k contract. So the ECI is not simply 1/365 (1 day out of 365 per year), but it should be something higher, maybe 20% of the contract sum? That's the risk.
If there is ECI, then there will be US tax in any case - the BPT would be on top of that.
Then there's the UAE side on top of it all:
If the US LLC is owned by the UAE company, then it would probably count as income of the UAE company in the UAE, as if the income was earned by the UAE company directly. So if you have a freezone company, it would probably count as income of that freezone company.
However, if you own the US LCC in your own name, then in theory, the UAE could say that your US LLC has a mainland PE in the UAE and that it's basically a mainland company that is completely separate from your freezone company (and if you didn't register for corporate tax, then you risk fines on top of UAE corporate tax). That seems rather far-fetched at the moment, but the new corporate tax rules in the UAE are as clear as mud at the moment.
I think it would probably be best to await further clarifications from the UAE tax authority. Until then, I see two potential solutions to avoiding the tax risk in the UAE:
1. Own the US LLC under your personal name, but register a freezone branch of the US LLC, instead of a UAE company, so it's clear how the US LLC should be handled in the UAE.
This might be a better solution anyway as your company would (hopefully) mostly fall under US law and not UAE law (liability etc.).
2. Add a nominee manager to your US LLC. That person should be in a tax-free country or a territorial tax country with very weak enforcement of PE rules. Then, if the UAE tax authorities really should come asking, you could explain that you are not managing the US LLC from the UAE, but that you're just a passive investor. (Can't really imagine they will come asking anytime soon, but if they do, I really can't imagine they'll start questioning your substance outside the UAE...) This approach would also completely avoid the headache with salary, corporate tax etc. - you're just a passive investor, no work is happening in the UAE, no PE, nothing... But that would also mean you'd need some other way to get your visa (like a Golden Visa or a separate freelancer license, or something like that).
It's all quite a mess at the moment, unfortunately.
I have already registered my freezone company and traveling in the next few weeks for visa. I hope I can update the freezone to be a branch of the US LLC and not have to set this up from scratch. That would be crazy.
The other thing is , will the US be sending reports or my 5472 to the UAE? Like how would this all play out in the UAE ( I know it's a mess there right now ) .
If I register for corp tax in UAE , pay my 9% with my freezone company. Does it matter that it's a branch of us LLC or registered in my name ?