I know he said that mostly to tease, but even though making the new boyfriend someone from another campaign comic hadn't entered my head, as soon as I read DragonTrainer's blurb, I felt instant relief. XD

Well, thinking about it, this arc is going to introduce potentially a new long-term PC - Vivi - whose player will then go on to play Nico Robin after Alabasta. So giving that role away to another guest visitor is a bit of a stretch.

Actually at this point it could be Rika playing Vivi and her (Boy?)friend playing either Mr.9 (the guy with the baseball bats) or Vivis bodyguard.

Yeah I think Rika’s vivi (And also chopper later? Idk) cause I’m still certain that DM’s Robin,

Plot twist: It's actually Rika playing Mr. 9 while the bf plays Vivi. Then Rika moves on to playing Chopper (and also Merry) later, while the bf plays... idk, Wiper after Alabasta? idk.

I don't know if i have said it before, but i strongly think that DM will play Robin. Robin first appearance was as a member of Barock Works, remember? I don't see Rika being the type to play a vilain or take over one as her new character.
Also, Robin started out as rather distant with the rest of the crew, Rika is the friendly type and tend to play kind-hearted character.

Robin's power would require a very good understanding of the rules, which Rika has...But once you realise that Robin's power is basicaly to grapple several opponents at a time, and from a distance, then you remember that Luke and DM are the grapple experts of the group.
And Robin must have some awfully large threatening squares, too. Putting accent on the reach remind of Luke and Cory's playstyle, who learned his min-maxing from Gordon, who learned from DM.

She also have a pretty deep backstory, but the other have no idea about it until Enies Lobbie, fitting with a remark DM made in a previous arc about how her creations have a backstory to justify how they are, but Cory and Luke never bothered discovering theses.

Finaly Robin could have died in Alabasta, but Luffy chose to go out of his way to save her.
My theory is that Robin will start as a antagonist, mostly played by DM. Luke will notice how proud of that build she is and decide to save her (remember how he spared Kurahado). All of that carefully foreshadowed by DragonTrainer.

Rika will play Chopper. Chopper has a Zoan fruit, and a particularly weak one at that, but can use it to a deadly effect thanks to the rumble ball. Being able to use 7 transformations instead of the usual 3 would take some severe rule-lawyering, and Rika have all the rulebook memorized perfectly. But on the other hand, Monster Point aside, he is not as destructive as the character of the monster trio, and not as quick to pick up a fight. So he is played by someone who know how to use the rules, but is not a powergamer or murderhobo.
Moreover, Chopper is a doctor, and Rika has expressed interest in playing a healer before.
Finally Chopper friendly personality fits with the type of character Rika enjoy playing, and a character who is a cute reindeer who gained human intelligence after eating the human fruit is the kind of idea someone like Rika could come up with.

Rika's friend huh? Are we going to see an overprotective Cory in a minute?

Am I smelling !future Franky?
I do think I am.

Might also be !future Brook, but I kinda hope that that role would be filled by a cool old(er) guy archetype.

Not sure if this is the best place to comment or if the author is going to see it, but the link to the "Knights of Buena Vista" don't work, I think they closed it.

Based on a blurb that got mixed up with Phil's notes earlier in the comic, I'm going to guess that Dressrosa is one of the original, non-module ideas being foreshadowed. If the Seven Pirate Warlords aren't a thing in the in-universe game's canon - considering Buggy (Gordon), Mihawk (guest character), Jinbe (Nat (implied)), and Boa (guest character (but only in a guest comic)) are all PCs - then Thriller Bark is probably also one of Gordon's (and Delilah's) original creations. I can see everything up to the end of Alabasta being modded modules, though. That's all I can say for sure at this stage, though.