Questions about process for contributing to OLM

HOT and Codeando did community testing on the mobile app two months ago with users and summarised the feedback by adding a list of suggestions on Trello. There are two specific ones we could potentially work on in supporting the improvement of OpenLitterMap (see below): https://trello.com/c/L1VRQxlF/212-translation-to-spanish https://trello.com/c/5H1lSUvU/211-make-an-onboarding-tutorial-inside-the-app

However, before we commit any extra volunteer time to work on this, we need to know:

Currently the issues are on Trello- should we move them to Github as issues? Or do you prefer Trello? I will be happy to add to Github asap.
Is this contributing.md the correct one to follow? Fork the repo and then send PRs for you to review?
What is the expected review time on Pull Requests? @xlcrr are you the only person who can approve and merge PRs or there anyone else who can collaborate with us/ we can tag while you are offline? Especially as we are hoping to contribute and help improve the translation at least by mid-July. @xlcrr can you provide answers ? Thank you!

OpenLitterMap / react-native