Considering a triple boot system, but I need some guidance

Hey all,

I’m waiting on some parts in the mail, but I’ll soon be upgrading a Dell Optiplex 3020 mid-tower and I’d like to triple boot it, with Windows 8.1 or 10, macOS Mojave, and Debian 10.

My specs:

CPU: Intel Core i5-4570 GPU: Sapphire Pulse AMD Radeon RX 570 4GB RAM: 8GB DDR3 Storage: 240GB SSD (boot) and 1TB HDD (storage) Wi-Fi: OurLink 600Mbps USB adapter, based off of some Realtek chipset. Amazon said it was compatible with macOS.

First, install order. I’m thinking Windows, Debian, macOS since Windows is fussy and macOS may be subject to reinstall if things go wrong. I’ll probably split it either evenly, with 80 GB for each operating system, or 120GB for Windows, 30GB for Debian, and 90GB for macOS.

Second, how would I go about these installs. Specifically, what do I need to know about triple booting and installing macOS?

Third, I’m a huge proponent of disk encryption. I’ve dualbooted Linux and Windows before with Veracrypt and LUKS; would something similar be possible with macOS as well? I don’t mind a small partition similar to /boot being left decrypted, it’s just the operating system and it’s files that I’m concerned about.

Fourth, although I have two drives, I’d prefer to keep this all on the SSD for speed purposes.

Thank you for any advice and help. If any additional information is necessary, feel free to ask.