Some good choices too (e.g. Plausible for analytics).
Only thing I wonder is, why I can only learn that you are Mailbrew Inc. from the PP or Terms of Services, and ...
> For our Patron in-app purchase flow, we collect related information such as payment amounts, times and currencies to validate and secure payments.
... that your revenue model apparently is in-app purchases?
Why not be more open about that with a nice About page where you present yourself and the product you offer.
(Note that this same feedback holds for so many services that are launched, where the lack of this transparency imho is an oversight).