I think the KISS principle should rule here. It's easy to get wrapped up in the future success of your startup and the precautions you should take now to protect yourself. I'd suggest not overcomplicating it and focus on other things that are more important.

Also, investors want to see you have skin in the game. I would expect to see a cash injection into the company. A note would lead me to believe that you are expecting the company to fail and you want to be in line before equity investors to get repaid in the event of liquidation. It'd be a red flag for me.

If you take on investors, there is a good chance they'll change the company structure anyway. If you have any questions, let me know and we can find a time to talk.