1.Play the champions you want. Being better at 2 or 3 champions is better than learning 20 champions especially if you are new. If I had to suggest something I would suggest Darius, Hecarim, and Malphite because those are all champions that are not gonna move much in the tier list and they are just good staple top laners to learn.
2. Counterpicking is not something you need to learn in low elo so don't worry about it and just play the champions you want.
3.Adcs are fragile and need some sort of help to get through lane phase and be strong mid or late game. Quinn is a good top laner but that's it.
4. Yeah, I am not sure if there are any YouTubers that main top and give nice information but Dyrus is a former pro so you can watch him to be able to learn and understand what he does and why and he is just fun to watch in my opinion. Here is his channel: https://www.youtube.com/user/TSirDiesAlot