You actually have a point (⊙…⊙ )
ithink that it'z maybe implied through the scarf that's worn by the person visiting the grave
No, that was the person IN the grave. It showed an old couple visiting the grave with a kid (no one was wearing the scarf), then the next panel it showed the person IN the grave surrounded by flowers, that was Mikasa (and the corpse didn't look that old, so did she die young?), then it showed the same old couple laying down a flower, so it was clearly Mikasa's grave, she was buried next to Eren.
I can see where you're coming--the old couple being Gabi and Falco--but I wouldn't say they're visiting Mikasa's grave, and I wouldn't say that's Gabi and Falco either (I think they're in the background where you see the wheelchair). Mikasa and someone accompanying her is visiting Eren's grave. There's a picture of old Mikasa's hand giving a rose to Eren's grave (her wrist has the bandage that covers her engraving/tattoo) AND THEN finally dying to show that time passed (remember the text is shown to be looked at from right to left rather than left to right). Because if it was Mikasa in that tree grave then it would contradict the Ymir-finding-the-tree parallel with the kid-finding-the-tree since Eren died (but died as a founding titan without passing it on), which implies that the cycle of the titan power will continue with the kid (as it did in the past with Ymir and look how that turned out: 139 chapters of AOT).
WAIT JK I think I contradicted myself XD sorry about that, it was shown from left to right as Mikasa dying and then people visiting the grave. My bad (￣∇￣")
That old couple is mikasa and someone who really looks like jean and i think the drawings mean that she visited erens grave with her whole family until the day she dies. If you look at the picture with the flower you can see thats an old womans hand and someone is holding her hand up so she can let that flower fall on the grave, because she is so old she dont have enough strenght left and needs help from the people around her and thats her last visit before she dies.
The panel before that one was clearly Mikasa's grave, as it showed her corpse inside it.
We saw an old couple visiting what was clearly Mikasa's grave. The old couple looked like Gabi and Falco with their grandkid. There was zero indication that it was Mikasa and Jean (it couldn't be since they were visiting Mikasa's grave). Plus, the previous chapter showed that Jean moved on from Mikasa and Mikasa was holding onto her feelings for Eren. So why are people suddenly thinking that Jean and Mikasa got married?