Just caught up with this thread. I liked the Episode of Sabo trailer, looking forward to watching it!
Regarding a few other points:
The dub is definitely not cancelled. They're still releasing One Piece content, just not the main story. I reckon once Episode of Sabo is released there probably won't be any further One Piece released until later in the year where they'll release maybe another TV special or two or something along those lines. Hopefully by then they'll have already announced Season 10 during one of the big summer cons or on their blog.
Straw Hat VA's have mentioned dubbing the body switch parts of Punk Hazard so they have definitely started dubbing it if they haven't already finished it. It will come out, it's just a matter of time. When that will be is anyone's guess. Personally I'd like to see it start releasing this year but I can also see them sitting on it until 2020 unfortunately.
As for Toonami, DeMarco said on his ask.fm a while back that currently there are no plans for them to put One Piece back on Toonami, however he did say that it wasn't impossible that it might one day return.
Someone also mentioned it being strange that FUNimation keep the simulcast but not the dub, but I remember back in 2011ish when it was still up in the air if FUNi would get Season 4 and beyond (man remember that wait?) that they stated they would continue to simulcast the series until it's completion regardless if there was a continued English dub or not.
As for asking them straight up, I don't think they'll answer stuff like that publicly. I remember reading that someone had asked them at a con and got a "can't talk about that right now" kinda answer so that gives me hope this is just a temporary hiatus and they're releasing these TV specials to try and boost One Piece profits before going back to the Voyage releases where profits will most likely return to what they were.