So I got a question for you GoGers who have purchased the HOMM V Bundle.

So my dad has the Steam Version of this game and I got the GoG Version and him and I know that Ubisoft shut off the servers for this game a while back and I was wonder if he uninstalled the HOMM V: ToE Steam Version and I have him install the GoG Version on his PC so we can play LAN Together just like the good ol' days. Cause him and I tried to see if we can crossplay LAN between 2 different Platforms. Seems like it doesn't work out that way.

I was wondering if anyone got a group of friends and/or family to install the GoG version on their computers to LAN and got it to work on a 2 - 8 player LAN Match?
or...
Does my Dad need to make a GoG Account and purchase the game itself in order for him to play LAN with me?

No, no, no, that's not how LAN works. LAN doesn't care where you have an account, and in most cases, where you got the game from.

You can either do it through physical LAN if you have a network set up among your home computers, or you can use a LAN emulator like Evolve or Hamachi.

But do you have a network set up within that modem, through which you can see each others' computers even within Windows Explorer?

Yes we did that. We don't know what the issues are.
I even made sure we're both hooked up on ethernet.

Could be either that your antivirus systems are blocking the connection, or that you need to forward some ports or even put your router in DMZ mode.

Doesn't putting the Modem on DMZ mode a risk?
We don't use anti viruses cause we only download from trusted sources.

In some cases it can be, but if you make sure you don't have other connections running, you should be fine. Downloading from non-trusted sources is not the only way you can get infected, just FYI.