The ONLY way I can see this working is if your parts can ALL be 3-D printed in their entirety or milled in under an hour. That then relies on a very very good printer set-up, likely one that you own and have used for at least a year (temp/humidity issues). You can do some electronics and PCB design with a mill and a copper plated proto-board (mill away copper plate and you can make crude PCB 'wires'), but you still need a fully functioning and stocked components chest or you have to wait a week for Digikey. If the zeitgeist is going towards IoT stuff, and I think it is, then you must wait for electronics parts to link the 3-D printed gizmo to the hackers waiting to make it a spam bot.
3 months is unlikely to be enough time to really get anything working without a well stocked lab.
It can take up to a month to receive a specific part for a prototype, and prototyping takes a lot more time in real space than in software.
I can change a class or a module in some code and 15 seconds later have the new version running. Changing a single part in a hardware system could take a day of work, changing both the software drivers and the actual physical hardware.
You can't just NPM install a new part and see if it works, you have to actually order it and wait for it to arrive in the mail.