Using XHCI, there are no predefined SMBIOS XHC1 identities (like iMac17,1 or iMacPro1,1) in Apple's AppleUSBXHCIPCI.kext, thus without any USB port limit patch, USB3.0 devices usually will not work in most of the USB3.0 ports, as most of the SS-ports will not be implemented (SS-ports have the highest port numeration, all SS-ports exceeding Apple's 15 port limit will be dropped by OSX). However, USB2.0 devices should in principle also work in the affected USB3.0 ports and in all USB2.0 ports, as all HS-ports usually are fully implemented by OSX despite the missing USB port limit patch (HS-ports always have a lower port numeration than SS-ports and therefore usually never exceed the 15 port limit). If you are lucky, at least one USB3.0 connector, usually one of the internal USB3.0 connectors (USB3.0 front panel connectors) associated to SS01 will also work with USB3.0 devices, if at least SS01 is still implemented.
Using XHC1, there are some predefined SMBIOS XHC1 identities (like iMac17,1 or iMacPro1,1) in Apple's AppleUSBXHCIPCI.kext with a preconfigured HS and SS port assignment not fully compatible with non-Apple mainboards. Thus it mainly depends on the predefined SMBIOS XHC1 HS and SS port assignment compatbitly, how many USB2.0 or USB3.0 ports will be functional on your motherboard.
For the XHC USB kext approach it would be better to create before any update to 10.14.1 a fully implemented board-specific XHC USB kext under some macOS version with a working USB port limit patch (e.g. 10.14.0 or 10.13.6). For its use under 10.14.1, you should drop the implementation of those USB onboard connectors, which you use less, by deleting the respective SS-ports and HS-ports in the kext, thus the kext finally only contains in total 15 HS/SS ports. By this, all USB3.0 and USB2.0 connectors will be fully functional under 10.14.1, apart from those assigned to the HS and SS ports, which you dropped from the kext.
For the USBInjectAll.kext and SSDT approach, RehabMan is the expert for explaining and providing you the correct solution.
Hope this little clarification helps somehow.