OcBinaryData VS Icnspack-Builder

HfsPlus.efi is missing, get that from this link and then put it in your Drivers folder: https://github.com/acidanthera/OcBinaryData/blob/master/Drivers/HfsPlus.efi

Fixed loading macOS with legacy boot without Apple Secure Boot: there is a new PE (Portable Executable) loader that broke legacy boot, blocking the loading of legacy drivers as HfsPlusLegacy and preventing OpenCore from booting on legacy systems when Apple Secure Boot is disabled. With this fix, legacy boot can work with or without Apple Secure Boot. This issue was detected after version 0.8.8 was released. While you are on 0.8.8, you must download the new versions of the drivers HfsPlusLegacy and ExFatDxeLegacy (the one/s that are necessary), available in Acidanthera. This is not required if you are on OpenCore 0.8.9.

Update Resources as well: https://github.com/acidanthera/OcBinaryData

Check if you have the latest resources Folder (included in OC Binary Data)

Copied from the latest OcBinaryData

I'm able to download and open up the zip as instructed, but as far as dropping the "ExFatDxeLegacy.efi" file into the right location on my ESP (which I understand to be my boot drive, where OCLP was originally installed), I'm at a total loss.

Have you tried downloading the version from https://github.com/acidanthera/OcBinaryData ?

Using a background from BlackOSx Gallery: BlackOsx Themes in particular BsxRedOldApple: RedOldApple it is noted in their readme that only one background should be in the folder as there are several different aspect ratios and rez's in the background folder. Since the machine I will be using is an HTPC attached to a 4K Roku TCL tv with a native resolution of 3840 X 2160 should the background icon be at the same aspect ratio when converted to a .PNG and double the rez ie 7680 x 4320 then converted to .ICNS using Icnspack-builder (IcnsPack-builder)? My current background at 5120 x 2880 converted is considerably smaller than the viewing area on my TV but fine on my 2K monitor. (2560 x 1440). Is there a max rez, and is 7680 x 4320 safe?

Follow dortania’s guide and after that use icns pack builder to convert your desired images into the correct format and replace them in the resources/image folder

You can also design the one missing if you want, or grab any other icons you like to replace these buttons (and use Icnspack-builder to convert the PNG into ICNS files)

https://github.com/chris1111/Icnspack-Builder uhm... actually, you can use this app by chris1111. Just push .png image to it, it will automatic convert to .icns, you will get the background

You have to use this on Github to make the icons. Then be sure to make the icons exactly 256 x 256 pixels.