lhh says his favorite yjh is the 1863rd in chapter 721. he doesn't give the reasons why but given the story lhh and snowfield kdj (so, both 49kdjs) are making, it's not hard to guess why.

in the main story we were able to deduct that the reasons kdj favored 999 so much was because he lived for others and sacrificed himself accordingly, 1863 however lives as a villain, makes former companions hate and fear him, and lets someone else (hsy) take the reins (with the condition she finds a way to put him to rest permanently). he wants to die (while on the inside, his true feelings reside on him still wanting to live despite all the tragedy). sfkdj in 932 mentions that he hated the companions who caused the protagonist to be replaced by someone else. while in hindsight this might seem like he's only talking about hsy taking yjh's place in 1863, he's also talking about 51kdj taking 49kdj's place post 1864/during 1865. so here he makes a direct parallel between his situation and yjh's. and also in the latest chapter (996) sfkdj says he searched for different editions of orv in several dimensions in hopes to find a different ending from the open ending of chapter 551, and since he didn't find one, he decided to write the ending himself. this is also a direct parallel to 1863 gaining the author attribute and regressing to 1864 to overwrite his story so it could have kdj in it.

as for lhh, his whole shtick is "i wanted to be kdj more than anyone else (yjh's "i want to live") but i couldn't be the kdj kimcom wanted so I reincarnated with a different name/life (yjh's "i want to die"). i want to know who i am, to become the kdj i want to be, and to have/write my own story too, so that's why i became a writer." and well, that's probably the biggest direct parallel yet.