devtrackers.gg
This is best case scenario. But I definitely get the feeling it's just "try StW for 1 month" then you have to buy it if you want to continue playing it.
Full, permanent access. Take a look at the new blog for more information!
They just posted the blog about it: https://www.epicgames.com/fortnite/en-US/news/deimos-rises-to-the-occasion-in-fortnite-crew-for-may
Skin is named Deimos and will also be a new Ninja in StW, does not say the perk so could be new or a reskin. Also StW access is permanent.
He will have an already existing perk. Homebase Status report will have the perk details.