I don' know if Isayama would write a sequel but my thoughts are that the kid is mikasa's and jean's and after the new war that happens he or she discovers the tree where eren is buried and then does smth and titans come back. but i really hope not because I think shingeki doesn't need another continuation.
Edit: I thought then that it may be Mikasa's grandchild as someone said in the comments, but that doesn't make sense either bc by the time she died she probably already had grandchildren and they probably fought in the war and then much time had to pass so that the buildings were swallowed by the earth and then much time for trees to grow around the tree where eren was buried. in conclusion we will never know who that boy/girl at the end is or if they are even related to mikasa or any of the characters
neither of them deserve to feel like that. hwi was so happy that he could have a date with param but bc of the guilt param was feeling it went down like that. param shouldn't have gone to the date or at least tell hwi why he was feeling like that even if it would hurt hwi, but would've been a better move that just leaving him feeling like crap and thinking he forced param into that date. or param shouldn't have done that with mr. han knowing he also has some feeling for hwi and then would feel guilty about it
OMG SHE LOOKS SO GORGEOUS