You don't have a top 10 pick in any of that though. I doubt Melbourne would accept 3 mid to late first rounders when they can get more than that elsewhere this year and next year.We're not locked into Houston.
We could offer 2 x 1sts (this year and nexts). We trade out Martin and Caroll out West, and Pittonet also gets traded out in the Ruck merry go round. There have been offers for Owies from a few clubs as well. Somehwhere in the middle of that we should be able to upgrade a 2nd into another 1st.
That's 3 x 1sts. Not low firsts, but it's 3 x 1sts. Probably around the best we could offer.
We have enough cap space for Houston. Forgoing on Houston, and trading out Owies, Martin and Pittonet, and we should have space for Petracca.
I doubt Carlton would drop Houston and I think they'd be stupid to do so for Petracca.