1) Again you can only talk about foreshadowing afterwards. What you just did was subjectively interpreting things as being 'foreshadowing'. That became extremely obvious with your examples. How many times do you think they are going to get a new ship? Usopp continuously trying to patch up the ship would at best be a foreshadowing that in the future they would need a shipwright, but that doesn't point towards anyone in particular. You just tried to see patterns so that you could talk about foreshadowing, but the fact is that many of these are extremely subjective and there are hell of a lot of differences between the Strawhats. On the other hand there are many other character that haven't joined fit several of these descriptions.
You can only talk about foreshadowing in regards to specific positions. Already from the start Luffy said he wanted a musician, which eventually ended up his last crew member nearly 500 chapters later and I can't remember any other position that has not been taken yet, so that would mean that no one will ever join? You can completely scratch this of your list.
2) I don't think that was the case for Robin as she wanted to die. Her dream is to find out the true history, but that's a tricky case as above all else she wanted to live an a place to belong to, which only became clear during the Enies Lobbies arc. Nami also just joined. She then left and then joined again, however Oda always said she was the 3rd member who joined and Luffy never considered her having left his crew. So she only revealed her dream after joining. Brook's situation is also a vey peculiar one.
So yeah Strawhats can join without proclaiming their dream beforehand.
3) The background story doesn't have to be given before the joining, Robin and Nami are examples of that. Likewise he gives a lot of background info on characters that will never join.
4 and 5) This counts for hell of a lot of characters as Oda goes quite far in creating unique characteristics for many characters. That one resembles another is, considering the amount of characters he created, quite rare. This works to scratch some characters, but most of the time by default characters will be unique in one way or another.
6) Franky and his gang beat Usopp to a pulp and stole his money which they consequently immediately spend on what can be considered selfish reasons. Zoro had already a reputation of being a monster and the first thing Luffy did was when he heard of him, was considering him as a new crewmate. Robin then just had been part of an evil organization. So "being good" is a very relative thing and can change over time as Luffy was cheering for Bellamy.
7) He gave the Strawhats a lot of things and he can give them these things at any given time.
8) It's not a minor point, it's simply not a point at all. It's completely irrelevant.
9) And Usopp, one of the weakling trio, currently is the only one who was able to awaken his Haki after Luffy, Zoro and Sanji. For some reason Oda still wanted Robin to have a higher bounty. Also outside the M3 and W3 there are only three characters left, so you in the end you have three groups of three. Before the time skip you could easily follow the pecking order for the last six, however post time skip that has become rather difficult. Who is stronger? Franky's robot attacks? Chopper's countless of transformations? Usopp's pop arsenal? Robin's massive limbs? The only thing you can be certain is that the M3 still is stronger than all of them, but among them Luffy and Zoro form a duo while Sanji seems to regularly fall out of it. So at this point it becomes extremely difficult to say where now you should draw a line. Jinbei however clearly is crossing it, so how you rated him as being of the same level as the middle group of Robin, Franky and Brooke I really don't get.
11) There are many characters that can be considered vital to the plot. The fact that even you are doubting which Strawhat you should connect with which BB pirate, makes this an invalid point as even if it would be the case, we only would know that for certain towards the end on a moment there will likely be no new Strawhats anymore.
12) How many Strawhats are actually important to the story? Or in the least could be considered important at the time they joined? Most of them really just joined and in reality are just there. Their importance lies in being a main character. I mean what kind of importance does Brook have? Laboon? Touching story, gives like many other things that much more depth to the plot, but in reality absolutely not important. The kind if importance things like these have is what Oda decides to give them and thus has actually nothing to do with being a potential Strawhat.
You tried to organize this entire "who is the next Strawhat" thing, but in reality you just added a whole new confusing dimension to it. This list is already simply way too long, several of your points do not have any relevance while others are very relative and several others then do not have to be immediately present, which makes them rather pointless to try to figure out who will be the next Strawhat. You're just shifting the subjective notion of who will join the Strawhats to the subjective notion of what the requirements a Stawhat should have. You can clearly see from your examples that there's something very wrong with your list as somehow people like Smoker, Tashigi and Kyros become serious candidates despite that their chances are nearly 0.
