Having not seen the actual contract, I thought that when it was originally talked about, it was said along the lines of "the character cannot be used on screen for two years following cancellation", not that they couldn't sign a contact before then.
If so, then, using last date of air rather than date of cancellation (I'm not sure which it would have been), then Hulu could air from the following...
Luke Cage S3 - 23/06/2020
Iron Fist S3/Heroes For Hire S1/Daughters of the Dragon S1 - 08/9/2020
Daredevil S4 - 20/10/2020
The Punisher S3 - 18/1/2021
Jessica Jones S4 - 2021
So, is it
...cannot appear on screen within two years of last air date
...cannot appear on screen within two years of cancellation date
...cannot sign a contract regarding a show for any character featured on the above shows for two years?
If it is either of the first two, then they could start filming them later this year to air next year.