For the first and second question the answer is yes, because it blocks ads, cookies, trackers this kinda thinks. Of course it is not said it is fully safe, it’s just protects you from analyzing algorithms and building profiles.
As for the third question, I think there are not necessary because brave has it’s bult-in Shield that blocks ads, cookies, trackers, etc. You can ask them to add these plugins but they will probably say no.
My answer is not really that accurate but this is what I can help with. I advise you to check their site for more information.