Thanks for the usual extensive response, it's appreciated. 
I have managed to solve it in a rather creative way, namely by having two components stacked on one another, one of which is the iFrame, which is simply outside of view (i,e. using "Overflow: Hidden"). Then, whenever I need it, I simply hide the sibling component, revealing the iFrame automatically.
Although this definitely feels a bit hacky, and dirty, it allows me to accomplish my goal for now, However, I had to forget about my Modal implementation, because that doesn't seem to support this due to the forementioned issues.
I think the key in this solution is to be able to asynchronously load other content, so it there was a way to simply have modules load by their dynamic path/URL, rather than having it load entirely on its own, users would be able to load ANY kind of module, instead of having to import all of them and then toggle between them using visibility properties.
I know, it's a moutful, but I think this is key to keeping apps performant and efficient.