I think Blade can definitely work as a supporting player in a Dr.Strange sequel, building up to a Midnight Sons movie with Ghost Rider. But a Blade reboot film doesn't seem like the way to go, especially if you recast Blade. Vampires don't quite fit with the MCU as we know it now, so Dr.Strange's mystical/supernatural world will need to come first.
As for Punisher, i think he would also need a new introduction, possibly as a one-shot. That short film Tom Jane did as Frank would work pretty well. His origin/backstory isn't that complex so a simple glossing over would work, as long as the writing is up to par. In a one-shot, Punisher is doing his usual business until he comes across a vampire den. Unable to kill the vampires by conventional means and backed into a corner, he is able to use sunlight to kill them. He then decides to find out where these vampires came from, leading into a Midnight Sons movie. In the movie, the Punisher will be the audience's viewpoint into this weird and dangerous part of the MCU. He runs into Blade, they fight, Dr.Strange breaks it up, enlists Punisher to help them beat back the vampires. Add Ghost Rider as the wild gun #4, and i think you'd have a pretty entertaining team-up film.
So i'd do this 'phase' something like this:
Dr. Strange film >> Blade one-shot/film >> Dr.Strange sequel >> Punisher one-shot/short film >> Midnight Sons Film