I think there is pretty good interest for Kap league wide so I would disagree with you on that. I could also see a guy like Lily moved if it is for the right RD partner for Rielly long term. I think AJ value due to injury is at an all time low so I would try to keep him for another year at least. He is a good younger player signed for 3 more season after this one at a fair cap hit for a middle 6 guy.
Honestly the leafs have been hitting on 2nd rounders really well to compensate for their lack of 1st round picks lately. Pleasantly surprised as I too was worried about the lack of picks. I also think the leafs will be moving out the depth guys for picks before they price themselves out of town so they will hopefully get some picks back. As a result I do think the next 1st round pick they have available could be in play.
The problem is there is no way the leafs will be able to afford Rakell's next contract. They will have Rielly, Anderson, Lily, Sandin, Kap etc all up around that time too. All this and the cap will have been flat. As a result Rakell would be valued at 2 years of term by the Leafs. Nylander contract is longer and they might even be able to resign him after it.
I'm not disagreeing that Rakell would probably excel with the leafs forwards. However many aren't thinking about the fact Nylander was pacing for like 37 goals and 71 points before the season was cancelled. He is just entering his peak years and is still likely to improve while being locked down for a lot of those years.
One small thing that I will point out as it has come up a few times, which is that while the long term usually would be a strong considerations Tor has appeared to have the philosophy of 1 year at a time going on atm, which is why they did a move like the Barrie trade. Now maybe they have changed their minds because of it, but everything over the past year or so that we have seen out of them, they do seem comfortable accepting future risk if it increases the odds of them winning in the now.