"All of my friends like dancing."
It says all of the friends which ask for the usage of 都 in the sentence, which already identifies 朋友 as a plural.
In native Chinese speaker, they also use "我的朋友" as plural. It is more fluency.
会 has two meanings. 1) 会="can"/"be able to" for learned skills. In this case it is the main verb of the sentence.
2) 会 means "will" indicating future tense, especially for events that will happen objectively in the future. (For events that you are going to make happen through your own effort, it is more appropriate to use 要). In this case it is a "helping verb" coming before the main verb of the sentence.
Wish there was a way to listen to the full complete sentence after getting it right (or wrong)
When I saw "all", I started going for 《所有的……》 , then i saw the word bank lol