Nah. He saw Shiro as a son. And was trying to prevent of him ending up like himself. That was his entire reason for everything he does for Shiro, whereas he did love Haru. Haru was like a safe haven for him. He allowed himself to be weak in front of Haru. Also, I don't know if you read the prequel but to me, while they tal about love, it was more like admiration and having someone who cares about you, much like a child with their parent.
I mean yeah at that point, but eventually their dynamics would have changed later on since Haru is not with them, they only have themselves and Shiro would have grown older by then.
Most likely not, shigure saw him as son so why would it change? Not only could it be a type of grooming but also I don’t think he’d start liking shiro in a romantic way because shiro grew up. With that type of thinking it’s like a parent who starts liking their kid once they hit 18 or something.
(Also sorry for replying 4 years later and for my grammar)
I still felt sad when Shigure cared a lot for and decided to run away with Shiro. If they were successful, we would have ended with Shigure x Shiro and Haru left alone. Shiro already has feelings for Shigure at that time with the way Shigure cared for him, it's inevitable that they would end up together in just few more years when Shiro has grown up a bit. While, Haru, broken-hearted, all alone and stuff. It just leaves a bad taste for me. Anyways, Shigure died and broke two hearts but at the end of the day Haru got a new love.