Man, I’ve had to read that play 3 times now (and act in it once–I played Danforth). This is definitely not a brag, but I absolutely know what you’re going through! The first time I read it I thought it was awesome, primarily because, in a syllabus full of poetry and other hard-to-decode-type stuff, The Crucible wasn’t particularly difficult to understand–the surface level, that is haha.
Anyway, onto your issue at hand. For any group project, I’d say that constant communication and accountability is key. First, start a group text and make sure everyone can access it. Stay in contact and check-in with the people in your group, enabling everyone to check the progress of the project. This will also make it easy to set up a rehearsal schedule and see what days work for everyone–especially if you don’t see them all everyday and won’t be able to talk to them in person about it. If you’re doing a PowerPoint or something as well Google Docs is my go-to for groups because it ensures that everyone is able to get into it and has no excuse (save personal crises, etc) for not doing their work. If your honors class is anything like my past ones, the people in it care A LOT about their grades and will more than pull their weight if their GPA is on the line!
Second, make sure everyone has an important (or at the very least, not completely meaningless/trivial) job to do. It sounds like you’ve got a LOT to do by yourself, what are the other members of your group doing? Make sure everyone pulls some weight and doesn’t leave everything for you to do. I’ve been in the position of sole contributer to a group project waaaaayyy too many times (I’m guessing you may have, too) and it really blows–especially when the project ends up being sub-par because it was thrown together by one person the night before it was due. I guess what I’m trying to say is it shouldn’t be your sole responsibility (group director or not) to keep your group afloat at all times.
Third, what do you mean you have to take care of costumes and set design? You have to create and provide them? Or just decide what the look should be and have your fellow group members dig through their closets for the closest match? Are you the only one in charge of like, painting backdrops and making props? That’s pretty rough, I would recommend asking some group members/friends for help with that–again, I don’t know all details of this project, so I don’t know what your other group members are in charge of, they could be bearing an equal or greater burden as you for all I know and can’t help you with that stuff, but maybe not 
I don’t have my copy of the play on me at the moment, is Act 3 Scene 1 the first scene in the courtroom? If so, I remember having a lot of lines as Danforth, and of course Proctor and Parris I think had quite a few as well, so check in with whoever is playing those people to see how things are going with the memorization (that goes for everyone, of course haha).
I’d recommend doing the memorizing and rehearsing/blocking in small chunks: If you have until May, you’ve got a fair amount of time to do it, so take is in small quantities and spend the last week or two perfecting everything (Or actually, now that I think about it, you could do the memorizing now, get it down totally pat, and then spend the last week or 2 creating set, props, and costume–that way the whole group can be involved and you don’t have to shoulder such a heavy burden by yourself).
Anyway, that’s all I got for now, I hope this helps you at least a little. Good luck with your project, I hope it goes well! 