@Yautja
I think it depends on what the underlying moral the author wants to portray. If he went with a romantic relationship with Jin + Lanka, maybe the underlying lesson would be how you can love anyone, no matter their race (species) or whatever differences. If the author wanted to drive home a "friendship becomes family" type of moral, then a non-romantic Jin + Lanka familial relationship and a romantic Hitomi + Jin would work as well. Seeing as how Lanka is a wolf/dog type character, I believe the latter theme would be a good conclusion for this manga, though I'm not sure if Japan has the same "Man's best friend" type of relationship with dogs like here in the States.
My "best end" would be Jin treating the pack as his family and getting romantically paired with Hitomi.