I adopted a street cat!

Hey everyone, I'd like to know that I've adopted a street cat 2-3 weeks ago, my junior came with the cat in college and asked if anyone can adopt him. His mother died on road and he was roaming and the street dogs here are kinda aggressive. My cat has urges to go out but I'm afraid that he will be killed by the dogs, how do I help him with going out and is putting a leash on him a good option? I live in appartments, I can't even let him roam there because of my dog lover neighbours, they'll not accept a cat roaming around, will hit it with a broo stick or anything, but will pet a dog like their own child Also how do I litter train him. Y'all s suggestions/Advice will help and mean a lot