I don't see relevant errors at the log file. The freeze sounds like a memory overflow. The RAM of the Gigabyte NUC should be large enough (still expandable by a swap file, if necessary).
Maybe it's the size of tmpfs. I can't change it on my RPi, but LE on PC is maybe different. Can you post the output of "cat /etc/fstab" please? That's the place to change tmpfs size on a standard Linux. When it's empty, we probably can't change it from there.
PS: A couple of days ago I guided another user, who installed LE from external to external device. So, I know LE is able to do this on modern PC's, but on most older PC's the BIOS is unable to do this. Take into account that old USB interfaces are usually slow, and an OS at such an interface will run slowly, too.
I'm using a 350gb hard drive, hooked up on a usb adapter I use to read hard drives and program them for pcs. It reads like a usb drive! But the libreelec creator won't pick it up, no matter how it's formatted 32gb 64gb or full 320 will recheck ntfs or fat only other factors that I can think of! Otherwise I should be able to program the drive and install it straight to the pc and run like a os
You said you can boot from USB, but it doesn't mean you can install from external to external device.
It looks like you want to use a modern USB HDD with an old PC. I think that doesn't works, because of the old PC's firmware (BIOS). Find a way to install an HDD internally (maybe use an adapter, if possible). I bet an internal drive will be detected by the LE installer.
Can you describe what installation image you are using, and what happens when you boot the image from stick? If it's a real installer, there should appear the option to install on your HDD.
PS: If you don't see any target drives to install, reformat your HDD with a tool like "GParted Live". You can run it from stick, too. It's interesting whether the tool can "see" your HDD while running from stick.
The result should be a single, error-free partition (ext3 for example) with no boot flag set. Try to run the LE installer on that setup.
So I just swapped it over and it all boots but Libreelec says the CPU is a ARM7 Processor Rev4 (v71) Is that right?
Will it just see all the new hardware bits and work better?
The LE image is the same for 3B and 3B+. Hardware differences will be detected on boot sequence. Processor info is wrong, but it doesn't matters (you will have the extra speed, anyway). Your installation is fine.
I had installed Kodi 18.1 (Linux Kernel 4.19.x) on a thumb drive booted the NUC and it ran the installer I plugged in another 32 gig thumb drive on 3.0 USB to be the main drive it installed with no problem. When finished it asked to remove the original thumb drive with the installer and reboot. Everything works just updating the library is taking days ! And yes never had to do anything special with the Raspberry's to run my Library from my cloud using NFS
P.S. No crashes but a lot of freezing
I'm very sure the target USB device is the bottleneck. Try to install it on an internal drive (SSD or M.2).
Read the post on top of this sub-forum. It was made for you. 
Hmmm never done that before ?
OK, if you never did special router settings for the RPi, then it's probably no router problem.
OK I setup a Gigabyte NUC Intel Celeron J1900 Mini PCup to 2.42GHz with 4 gigs ram running Kodi 18.1 (Linux Kernel 4.19.x) off a USB 32gig Thumb drive.
I don't understand this. Do you run LibreELEC? Do you run an OS at "live" mode directly from an USB stick (that is slow for sure)?
So it appears its kodi.bin, its using around 49 % when just sat in the menu.
Any ideas?
See post #2 (it's a proof of my GUI theory)
Is there some tweaks I am missing ?
You have a new MAC address now. Maybe you have to fix some router settings to speed up data transfer.
Can I change the size of tmpfs?
I don't know. I did it for my Ubuntu Linux by editing /etc/fstab, but this doesn't works on LE.
2019-04-14 17:25:07.237 T:1742455664 WARNING: Process directory 'smb://USERNAME:[email protected]/SERIES/delete/' does not exist - skipping scan.
Maybe this would be a cause? I already c reated a swap file too ( if not enough memory) but this doesn't change anything either
No, it's Samba stuff. You can deactivate Samba at the LE services settings, if you don't use it. You can deactivate Wifi at the network settings, too, since you are using Ethernet.
If a swap file doesn't helps, it's maybe the size of tmpfs.
I saw something about wlan as well, so followed this guide to blacklist wifi. But didn't help:
Create the file /etc/modprobe.d/raspi3-blacklist.conf by adding the following entries:
#wifi
blacklist brcmfmac
blacklist brcmuti
The rpi runs over (POE) Ethernet
I'm using an RPi3B+ with Ethernet only, too. There is no need do deactivate Wifi by blacklist any driver.
Thank you, but this log doesn't tell what we need to know. It has no significant errors.
Activate log level 1 by creating the file "/storage/.kodi/userdata/advancedsettings.xml" with the content:
<advancedsettings>
<loglevel>1</loglevel>
</advancedsettings>Reboot, reproduce the error situation and post "/storage/.kodi/temp/kodi.log".
Unfortunately the output doesn't represent the error situation. Activate logging and try to reproduce the error. At the log file we can see whether it's about SD (tmpfs) or RAM space.
This was not your question, but I would think about creating a swap partition, when it's just about RAM size.
This means, you need significantly more processing speed, compared to an RPi 3B+. You should go for a fanless HTPC. There are nice aluminium cases out there.
PS: This thing runs Ubuntu, so all drivers should be there to run LE, too: Cirrus 7 Nimbus
PS: Look at line 2 of this post to learn how to play something from a script.