What does "fashion-froth" mean?

"They are my friends playing football in the playground" Is this sentence correct? In the textbook it is written "I'm in bed, because I'm ill. Looking through the window is my only fun. Look. ______ are my friends playing football in the playgroud." So, I think that the right answer is "Those", but I am not sure. And is it posible to be "They"? If it isn't, why not? Is it possible to have this construction in the sentence? Like, "He is my boyfriend sitting next to me"?

아니나 vs 아니야 Why in here "사람은 아니나 사람의 모습을 한 요괴" it is "아니나" and not "아니야"? What does this "나" stands for?

What does 하두 성화 means? In the sentence '주말에 같이 놀 친구하나 만들라고 하두 성화해서 나온거에요.' Thank you :)

What does "말 드럽게 많네!" means?

What does 햬쳐먹었는데 mean? In the sentence 이거저것도 나 햬쳐먹었는데 이것도 때 먹개?

뵈로 << - What does this mean? I have heard a lot of "뵈로 온다" and "뵈로 간다" but I can't figure out what this means.

Are there any case where I can use "You can don't see it" ?

What is the difference between 可以 and 能? Or can I use any of them? I forgot to add 会!