Responses

Jealousy starts - the scenes with Reika and Hachi - years after the end of Yondaime. Reika was only in preschool in Yondaime after all. She's much older in Jealousy. The story has been on an extended flashback. So no, the 'present' story line is a sequel to Yondaime. We're just stuck in the past for a bit. I can only assume sensei will take us back to the present storyline at some point to develop the relationship between Rogi and Hachi.
99.9% sure that Rogi x Hachi will be end game.
The paradox of this story is probably that in the past (in this manga) Akitora was worried about Uichi becoming bored with him but in the present (the sequel) it's actually Akitora the one who left Uichi alone.
... I just feel so sad for Uichi ╥﹏╥