Hi Jason, thanks so much for your very detailed reply.
I have immediately implemented your 2nd option that you also have working on your test site and it indeed immediately works perfect. I only noticed that the slider now also pops up on this page, so I will need to dive into the theme to see how I can disable that…
Regarding the future posts I admit that it is weird and on my own test setup it works as it should as well. I will have another long look at the different plugins that have been installed on the site. At least we can now conclude that it has nothing to do with your theme and/or WPML.
Regarding the category names not showing up correctly I think it has to do with what you wrote:
I will admit this is probably not ideal with working with WPML because you’d have to ensure that you never opened and saved a layout of one language while under another language. This could get messy in the long run.
Let’s leave that for now as it is working on the homepage now and if it would fail in the future (I don’t believe it will) then for the homepage we can also implement the post list page template.
Again, many thanks for your support!