1080p h264 video files are the easiest to handle by all recent video devices.
Judging from you log file, your attached screen does not support 1920x1080 at 60fps, only upto 30fps. I'm not sure what resolution is used now.
Can you connect via SSH and give the output of
xrandr | paste
and share the URL?
display refresh rate on or off
On => Start/stop. This will set your TV's to the correct or closest refresh rate based on the video's fps details. If you are watching on a pc/laptop monitor, disable it.
At this moment I haven't changed anything and the video files (All local) plays really well.
Don't fix things, if they aren't broken 
It probably has nothing to do with your video problem, but your system does have repositories and likely add-ons installled were are on the banned list of Kodi. Add-ons that can affect core Kodi functionality, let along the whole illegality of it.
So remove -all- that extra luggage, or just simply start with a new & clean setup, so the technical side of things can be looked at.
We're not going to give support before that happens, as you could have known from the LibreELEC forum rules when you signed up.
1080p videos with HW on (vdpau) like H.264 should be no problem with a 660 or 730 card.
I'm not too sure about VC-1 myself (I'm not a developer, and I don't have VC-1 videos).
The main component for Kodi and video play remains the video card. The PC chipset is less important.
Which Nvidia graphics card are you referring to?
I have a problem with the OpenELEC resolution
I'd start with upgrading to LibreELEC, but I assume you simply made a typing mistake. :o)
What other device specifically is this non-bootable USB for?
As far as I know, we only support audio stuff via Bluetooth, and not file transfers.
Disabling Bluetooth while using a BT keyboard and/or mouse is indeed a .. challenge. 
Please familiarize yourself (again) with the LibreELEC forum rules to which you agreed upon registration.
Advertisements or links to commercial products or services are not appreciated here.
Things are in motion for Amlogic. I'd say let's get it working properly first, and deal with "less cpu consumption" later. If things work properly, the GPU will have to deal with most of the effort, while the CPU automatically can take the proverbial rest.
Open a SSH session to your Beebox, and give us the URL of the following command:
dmesg | pasteThen we can see if Linux itself cannot find the BT adapter, or that it's perhaps a driver problem.
5 Kids folders and 8 Movies folders... How did you manage that? 
Using unique folder names would be helpful to begin with in my book. 
AFAIK, LibreELEC has no default functionality that will cause a reboot at a certain time. So it must be one of your installed add-ons.
A couple of things for now, IMO:
- If a totally fresh install of 8.2.5 only (no other addons) doesn't get BT audio to work, it could be a hardware problem.
- Did the Bluetooth Audio Device Changer add-on recently get an update? It might have a bug, seeing the kodi.log entries. Contact its developer(s).
- LE 8 = EOL, and will itself not get any more updates
- Try LE 9 Alpha 3 for more results.
I've been running multiple boot systems with Ubuntu and LibreELEC (and Windows..) for quite a few years now.
Setting them up is pretty easy when using Ubuntu's GRUB menu.
The addons and the userdata folders from the .kodi profile folder should be enough, but 'YMMV'.
It's names and numbers we need. Please provide a debug-enabled kodi.log file (via a paste website) for some initial detailed info on your RPi box.