Why are certain areas of my template grayed out and/or don't appear at all?

Just like the title says, after creating a template for an '02 Suburban, some areas of the template, specifically any parts from the front bumper, are grayed out and cannot be selected or manipulated in any way. They also don't appear in the render nor export with the template. The only workaround I've found so far is to retemplate those areas but that's a lot of work that I don't really want to do. Am I just doing something horribly wrong as I'm very new to templating vehicles, or is it just zmod having one of its "moments"?

I'm also having a problem where the renderer doesn't load large parts of the template despite their objects being visible on the different viewports as well as on the UV mapper. They don't export with the template either. I literally don't know how to fix it, but sometimes it works for me to hide all objects and reshow them, although that isn't working as of right now.

I've attached some screenshots below. Any help at all would be appreciated.

This demonstrates the grayed out bumper issue:

This demonstrates the missing parts issue:

Quote from Nolan8024

Before you render the template in ZMod, make sure everything that's everything is on inside the hierarchy that corresponds with the template. I've had that issue before and some of my parts were shut off, so I checked the parts that corresponded with the template and rendered the template once again.

I tried hiding and showing the objects, that did absolutely nothing. I tried hiding and showing the objects within the UV mapper, all that did was remove the hood, roof, trunk, and plates from the template and forced me to re-map those parts.

After that I don't know what I did now but now nothing on the template can be selected, there's no objects in the objects dropdown in the UV mapper, I can't get the template off the UV mapper, and clicking on its material in the dropdown crashes zmod. I swear this program was designed by drunken monkeys.

After switching the UV mapper to a different view everything's gone, is there a way to recover the UV maps without having to individually select each polygon again?