Yeah, it is important to note that the RP is going to start just as Sakazuki is giving his speech as he is introduced as the new Fleet Admiral. So try to think about how your character would be reacting to this news and what they would be doing exactly, but I'll go into that more after everyone's characters are sorted. We have plenty of time though so no need to feel pressured into rushing.
Also I added a Music Skill and I sort of clarified some things with the Medicine and Cooking ones. Like how long certain effects and skill alterations last.
And yeah, if another character, such as Daz Bones, already has a DF then that DF is taken. However, anime filler characters, and basically characters that aren't from the manga, their abilities and DFs are free to have. I won't count them. Though I'll be pretty lenient. It is One Piece after all. If there is a fruit ability you want but it is already taken you can sort of try to come up with something that is similar but still different. Like how there is a Snow and an Ice Logia fruit.