To be honest, I doubt that most of them are likely to join the strawhats, the only two characters I can imagine as part of the crew are Kinemon and Jimbei.
In my opinion it's very safe to assume that Jimbei will join them one day, once the problem with Big Mom is solved because thats pretty much what he said back on Fishmen Island.
And also Kinemon feels like a good addition to me, toghether with Momonosuke. Right now everyone in the crew has a unique and pirate-ish purpose: Luffy=Captain, Zoro=Vice-Captain (although this is not really confirmed yet), Sanji=Cook (insert "wait who was that guy again"-joke here), Usopp=Sniper, Nami=Navigator, Robin=Archaeologist, Franky=Shipwright and Brook=Musician
Kinemon could be the Tailor (not really a important role but hey) and Momonosuke the Cabin-boy, kind of like Shanks and Buggy on Rogers Ship. Jimbei's role maybe something like a "symbol of peace between the two races". The way it looks right now is that Kinemon and his son will stick around with the Strawhats for a fair bit longer, like Vivi/Bibi during the Alabasta Arc. Luffy offered her to join (but she decided to stay in her country in the end). Still I think you see where I am going with this --> I believe that at the end of their shared adventures Luffy will ask them too.
Also all of the strawhats have a dream, a goal they want to achieve (Luffy Pirate King, Brook Laboom,...). Kinemon and Momonosuke don't have that yet, but I'm sure we'll find out more about them later on in the series. Jimbei's dream could be something like solving the conflict between people and fishmen, who knows.
Law: I heavily doubt that he will abandon his crew and join the strawhats. Him and Kid were shown as equals to Luffy on Sabaody Archipelago, and also now with the alliance as two captains. I think the relationship between Luffy and him will be kind of like the one between Roger and Whitebeard in the past.
Bellamy: I don't see him joining either, yes Doflamingo betrayed him and he has nobody at the moment, but I still don't think he would really fit in with the rest of the crew and their dynamics (Momonosuke for example fits in perfectly in my opinion, since he always makes Sanji, Brook and Kinemon jealous of him) Manga Spoiler
Cavendish: Manga Spoiler
Rebecca: Since her character is kind of meant to no fight/having to fight Manga Spoiler I just can't imagine her leaving her family she just won back to sail with the strawhats..
Ceasar Clown: No way! NO WAY! Please tell them Usopp! It's true, not every member of the actual crew was best friends with Luffy from the beginning, for example Franky (who wanted to revenge his family). But they all were/are good people on the bottom of their heart, not like Ceasar: This guy is freaking evil!
Violet: I think and hope she will stay in Dressrosa. Her powers would take away the fun and exitement of every new island the strawhats visit on their adventure. Also, just like Rebecca, I doubt she will leave her family at the end of the Dressrosa Arc so quickly after their reunion.
Leo: I guess it would be cool to have a Dwarf on the ship too, but I don't really see a reason for him joining the crew. I think it's more likely for him to stay with his tribe. Don't forget that he will be buisy with building a giant statue of our Lord and Saviour God Usopp. :P
Bartolomeo: I personally think it would be funnier for his character if he never actually is allowed to join Luffy.
But hey, that's just my opinion! I still liked your video and the music :D no hate <3 I didn't want to make you feel bad or something, just share my thoughts. This has become a pretty long post.. I hope i didn't make too many mistakes :)