Questions from a newbie

Thinking of porting two numbers from ATT postpaid to dark star BOGO promo on the annual plan. I have a friend who has US Mobile now and was wondering if I can use his referral link and does it stack with the annual plan or would it only work on the monthly plan?

This sounds really stupid, but on the premium and starter plan is the international data of 20GB and 1GB per month or is for the entire year? I assume it’s monthly but the website isn’t deliberately clear and the terminology gets a bit muddy since only the annual starter plan includes it.

Has there been any talk about doing Apple Watch on dark star or light speed?

Any tips for a new customer? Bummed I missed out on the OVERDRIVE promo code but such is life.