Looking for Advice on Charity in Islam

Salam everyone, I grew up around a lot of Muslim friends and neighbors, but now I’m living somewhere where I don’t really know any Muslims personally, so I’m turning here for some guidance. There’s a situation involving charity that I’d like to understand better from an Islamic perspective. A younger relative of mine was struggling with addiction and homelessness for a while, alhamdulillah he’s been clean for almost a year now and is rebuilding his life. Back when he was in a really tough spot, two local halal food places in our old area fed him for free every day, knowing he was using drugs. They never gave him money except once, when they stopped him from taking money from a sister in hijab who wanted to help but was poor herself-they covered it themselves instead. I’m familiar with the importance of charity in Islam, like zakat and helping those in need. In my faith, we’re also taught to be charitable, though it’s less structured. I really admire the Islamic approach to giving. I have two questions: 1. I want to thank these shop owners and maybe donate to their mosque. Would asking which mosque they attend be awkward or disrespectful? Should I instead donate to a general cause without mentioning it? 2. Separately, I’d like to show gratitude to the Muslim community as a whole, recognizing that their kindness comes from Islamic teachings. Is it okay for a non-Muslim to give zakat? If so, can I give 2.5% directly to a charity like Islamic Aid, or does it need to go through a collector? Also, would a trusted project helping Gaza (like a school for children) be acceptable, or does it have to be a registered charity? I hope I haven’t said anything wrong-just trying to learn. Jazakallah khair for your help.