It certainly can be done but what you're going to run into is some of the venders here to get quality parts have wait times in the months. Speaking of the helmet specifically since you're on a tight deadline I would recommend Tommyboy, ToEleven, and Wasteland. I have no idea what their current wait times are but from what I'm seeing Animefan, Darth Voorhees, Bobamaker, and Fettpride probably wont be able to get you a helmet in time. That doesn't mean that it wouldn't hurt to contact them because everyone I mentioned makes great helmets. I'm sure I missed some other makers as well. Another option is to look through the cargo hold and see if any helmets are up for sale right now. Even though you're a new member and can't post in the cargo hold yet you can still PM the sellers to get in contact with them. If you have any questions use the search feature to help learn and feel free to ask. Good luck with your build!