Ekblad just turned 23 though, he fits in with our core age and has been trending upwards defensively and on pace for his normal offensive stats. We'd be interested in Stone but only in free agency, we would not trade a core player for the hopes of getting Stone/Duchene locked up long term. Similar to the Bob/Panarin talks for Huberdeau. Just doesn't make sense asset wise to take all the risk of the player signing elsewhere.
If Ekblad was maybe 26-27 and was stalled in his progression, then we could start talking but at this point in Tallon's decade long build, we want to add another top 4 RD to start contending.
As a OTT fan, you just need to recoup 2 1st round picks, a 2nd and a couple prospects for your big 3 UFA free agents and continue to draft and build your new core. I don't think you're too far off, hopefully Dorion can sign some decent stopgap players to shelter your rookies/ELC players. Should be another 2 years and you guys will be on your way to a young and upcoming team.
One guy is 25 with 5 years left and the other is 31 with 2 years left, don't see a deal to be made hear with Petry as the main piece. I created a trade thread for Petry last year and most agreed to it but I'd hope our GM could land a 23-26 yr old top 4 D with term for Huberdeau. Would be pretty shocked if Huberdeau is traded, his chemistry with Barkov is pretty magical and the last 2 games have reminded everyone of what they can do together.