[the_jaguar]

What guide?  Your PCF.xml isn't like anything exampled here and your .bat looks to be from Windows 7 era which also isn't like anything exampled here.  What O/S and GPU are you using?  It looks like you want to use MPC-HC for everything including 3D except you want to use internet streams with the Kodi player.  It also looks like you want MPC-HC to do your mounting and forgo VCD.

These two rules conflict with each other and not only that, I've had problems using multiple rules of the same type:
<rule filetypes="iso" player="isoPlayer"/> HERE you are telling MPC-HC (via your .bat) to open iso's by mounting with MPC-HC itself instead of VCD.  Some say MPC-HC auto mounts iso's.  I've never had success.  Good luck. 
<rule filetypes="mkv|avi|bdmv|mpls|m2ts" player="MPC-HC"/> HERE you are telling MPC-HC to open bdmv, m2ts and mpls (I assume are in your unmounted iso) which means it isn't mounted either and you want MPC-HC to auto mount so you can access them.  Again, good luck. 

I don't know how others get MPC players to handle mounting iso's internally perfectly but apparently it doesn't work for you either.  Maybe ask them or change your codes to how it's done here by using VCD.

You can verify if YOU are able to open an iso with MPC players by right clicking your iso in Windows Explorer and selecting 'open with' and then selecting MPC-HC or MPC-BE.  I can't but others say no problem.  Start reading here https://www.avsforum.com/forum/26-home-t...st57821568

I used the guide from page 1. I copied most of the text for the BAT file from your guide and made some minor changes. Regarding PCF.xml, I had it setup earlier to open MPC-HC for all types of files (except internet streams) and I modified the same file to now distinguish between ISO files and non-ISO files. In the BAT file (PlayISO.bat), I am calling VCD to mount drive A with the filename of the ISO. Shouldn't that mount the file? Sorry, this is new to me since I am coming from a non Windows platform where I didn't have to do any of this (mac, rpi, Android).

Like you suggested, I tried mounting an ISO file with MPC-HC, but it didn't work as expected. However, it does mount and play fine with MPC-BE.

Update: Given that MPC-BE is able to load the ISO automatically without having to use an external mounting software, I am going to try configuring madVR with MPC-BE and go down that route. Let's see where this takes me.