It will work without those regulators, so if you don't have specific plans for 5v or 3.3v rails, just build ahead and get them when they're available again.
When I messed with arduino 15 or so years ago, it was all straight C. I think there wasn't space for the OOP libraries. I assume things have advanced somewhat since then....
Check out ampgarage.com. several of those dudes seem to really know what they're doing. If you need help troubleshooting, you'll need to be able to supply schematic, voltages at various points, etc.