I don’t think Loki needs to sleep. His powered by magic, but it would be cute to see Thor trying to convince him to sleep. Loki is hardly the sort of toy someone would want to sleep with - he’s not soft and he’s cold to the touch being made of metal, but Thor doesn’t care. He’d convince Loki to lie down with him and would embrace him. Loki would listening to Thor’s heartbeat slowing down and try to mick it with magic, slowing the whirl of his cogs so he could fake sleep. 

In regards to Hela, no, she’s not going to be Queen. Asgard has always seemed very patriarchal to me - Sif being a warrior women is considered odd, the Valkyrie and Hela are airbrushed from the history of the Kingdom and the building of it’s empire, the very fact that their rulers Odin and Frigga are known as the All-Father and the All-Mother. So I think Hela’s right to the throne has been superseded by Thor simply because Thor was born with a penis.