You forgot about Itachi as well... The fillers might go over to Danzo, Kakashi and Itachi in three weeks, I can see that happening. However anyway, if you read it on Saiyan Island, then Itachi as a anbu will join the fight against Kakashi.
Not sure, but it's going to run well into April. I think after April 3rd there are fillers going to be shown about Itachi, Yamato, and Kakashi in their Anbu days.
They are going to show Itachi interacting with Kakashi and Yamato in April. Also, I do believe they are going to show scenes of Itachi and him dealing w/ double spying and the whole mess w/ Fugaku/Mikoto/restofUchihaclan's coup.
Well considering Itachi is Entering next weeks episode, I'm gonna take a guess and say it'll return to canon between mid and end April. Itachi after all was the last "Main" character for this arc to be introduced wasn't he? That would give 3-5 episodes with him in (5 by end April) Judging by how long we've had them so far. Most probably wrong but that seems right to me. Hope it ends sooner than later though...