IF RE-INSTALLING DIDN'T HELP YOU with MOUSE and KEYBOARD.
As of Jan 2018, I just did total clean install of High Sierra including erase all volumes and partitions.
Unfortunately, BootCamp Assistant(BCA) failed to install drivers, so I had to copy install files from manually downloaded file.
I ran BCA setup tools several times but I couldn't get it working properly.
Symptoms
When Apple Wireless keyboard is connected, connection notification icon is not visible.
Can't use right click, or scroll.
Solutions
Make sure you already installed BCA drivers.
Do NOT disable HID Mouses, one for TrackPad and Apple Mouse.
Open Device Manager by pressing (Windows+X, then choose Device Manager),
Under "System Devices", find "Broadcom UHE Serial Driver".
Right click and select "Driver Update".
Windows will update this driver, then it will change the name as "Broadcom Serial Bus over UART Bus Enumerator".
Now, Windows starts to detect my keyboard and mouse.
However, unfortunately, I lost control of my mouse at this point.
Restart Windows.
Now, you have your mouse and keyboards under "Bluetooth" section from Device Manager with your name.
Once again, you still need to keep HID Mouse. Do NOT disable or delete it.
Also, I'm not quite sure about this but it seems like Apple Starts Up Manager handles Bluetooth when user selects Bootcamp manually on startup by holding "Option" key.
When you need to install/update drivers for Windows(Bootcamp),
make sure you chose "Bootcamp" explicitly via "Startup Disk Preferences" in MacOS.
Also, make sure you run "Apple Software Update" because Apple released new driver which make you be able to wake up Windows by wireless keyboard and wireless mouse.
Good luck.