Alright... finally got LSPDFR to work again!! Woohoo!! Thanks so much @UnknownBastion for all your help You were right, it was about files being blocked. VERY much appreciated! I'll rewrite Bastion's advice below but with a little twist. Found out several things while trying to get this to work.
*DISCLAIMER - This worked for me but can't guarantee this will work for you. If your computer explodes on you, please do not blame me*
So I basically followed Bastion's advice in unblocking files but as those who've been reading up on this post know, I didn't have an "Unblock" button in my file properties window. Then I found out how to add a working "Unblock" button and was able to begin unblocking files one by one. But I really wanted to find a way to do this faster and so now I found out how to unblock files in bulk using Powershell. Once all was done, LSPDFR started working for me again.
So for anyone who's having the same issue I had... with this method you should be able to get LSPDFR up and running again (can do this for all your mods as well prior to installing them, if you so wish). Just please keep my disclaimer in mind, I'm not a programmer/developer by any means. Only with Bastion's help, along with info I researched and through trial and error I got it working. You shouldn't run into issues if done right but can't guarantee that.
Anyhow, here's what to do (before performing any of the steps, read the whole process first, even the "Note" at the end):
1 - Download latest LSPDFR (manual version, not auto-installer) and latest RAGE Plugin Hook. Create a new folder in D drive (can be C drive also) for each of the downloads and extract each zip file into it's own folder. Name folders whatever you like.
2 - Press the "Windows" + "R" keys. This will bring up the "Run" dialog box.
3 - In the Run box type: powershell. Then press "Ok" or "Enter".
4 - In Powershell, type this command: dir -Path "D:\Your Folder's Name" -Recurse | Unblock-File then press "Enter".
5 - Repeat this for the other folder.
6 - Once the above command is run for both folders, copy and paste FIRST the LSPDFR contents (except the 'licenses' folder) into your GTA V directory, replace all files if prompted. Then copy and paste the RAGE Plugin Hook contents into your main GTA V directory, replace all files when prompted.
7 - Start up the mod and it should be working now
NOTE: In the command snippet, the "-Recurse" parameter is used if you have files in sub-folders, as is the case with the LSPDFR files once extracted. Apart from LSPDFR, if you find there are no sub-folders in zip files you extract, you can leave out "-Recurse". If you wish to perform a test prior to unblocking the files, just put the "-WhatIf" parameter at the end... dir -Path "D:\Your Folder's Name" -Recurse | Unblock-File -WhatIf and run the command. This will do a test run and show you what will happen with the command you're using, without actually doing anything. All fine? Then you're good to go. Type in the command again, without "-WhatIf" to unblock all files.