I'm new to the whole hackintosh thing, and I recently purchased all the parts in this build. However I have a few questions
1.) I read on
@dracoflar 's
GPU buyers guide to avoid "Sapphire" branded cards will this be an issue?
2.) Will FaceTime/iMessage work?
3.) Will I be able to update to Catalina when it releases? (with "sidecar" working)
[edit]Is there anything else I should be concerned about with this build? (i.e: app store working etc.)
Sapphire is actually the preferred GPU, I have working a Pulse RX580 and Pulse Vega 56. No hacking required, though not all of the monitor connections work, so you have to use ones that do or apply a little hacking.
Yes, all of the Apple services can work if you do the necessary predatory work, even Airdrop and Apple Watch unlocking can work if you buy Apple WiFi/Bluetooth hardware.
Not sure what a side car is, but Catalina should work fine. You will probably want to wait for a couple of months and check the thread to see what kind of problems the risk takers experience and for the community to update Clover and kext if needed.
Personally, if you don't have a real need for Thunderbolt specifically I would not do that again. Very disappoint when you've used Thunderbolt on Apple. It does work.
With that much stuff to get working it will probably take considerable time, even if you follow the guide perfectly you can still have issues. Oddly every hack can be it's own little snow-flake. This usually comes down to very slight difference like BIOS version, not the identical graphics card or some other seemingly unimportant detail. The closer you get the better. Have Patience, one check box can make the difference between perfection and a boot failure. I wouldn't connect to the Internet until you've verify your system using iMessage_debug and comparing the values between reboots. Then check DPCI_manager to verify the network is built in. This is covered in iMessage guide. Do this before connecting to the Internet or logging in to any of the Apple services. I like to tune the /EFI folder on the USB thumb drive to perfection because I can plug it in to my real Mac and use Clover Configurator to try things without the pain of what happens if it doesn't boot from a mistake. I will use UniBeast. Then, when finished, open config.plist on the USB installer and set the system definition and generate good numbers in Clover Configurator, delete the unneeded kexts in /EFI/Clover/kexts/other, then any additional settings. Depending on the completeness of the guide you can get an awful lot of the work done before even booting hackintosh for the first time by doing the work on a real Mac to the USB drive. Then, back up and then transfer the whole EFI over to the internal drive as a last step. Take the USB installer and hide it in the computer so you have a recovery and backup copy of the EFI.
Take lab notes as you go so you can refer to it next year when a new OS comes out. Things like kext names and version, where you installed them. Don't forget any details about why you did what you did. I would also have empty folders on the /EFI partition like "usb_installer" and "system" so you are less likely to get confused about which EFI you have mounted. Don't mount 2 at the same time.