My point is that these things are subjective. I get this unsolicited advice is coming from a good place but it's just your random opinion. Let's leave the parenting up to the parent.
It is unique. There is no guarantee that this would work in any other language unless you found two voice actors with the same level of natural skill and collaboration (I'm sure it must have been tried). You can't write out the dialogue in Czech, translate it, and have it dubbed in various languages; the ad-libbing seems essential, and I'm sure any attempt to replicate this would fail if you didn't get two actors who not only completely grok the show and its protagonists, but also know how to apply the local tropes of this type of character correctly.
But it works. There are few countries where Pat & Mat are as popular as the Netherlands. In fact, it's probably only Czechia itself which tops that. It's not that Pat & Mat were lacking anything — the silent shorts are brilliant in their own right — but the Dutch dub adds another layer of humour which so completely matches the feel of the characters in the show that it doesn't detract at any point. A lot of Dutch don't even know that it is only here where a dub is used, and that the affable dialogue added was never intended!
The only weird and regrettable thing (for a variation of a Czech show) is that you have to understand spoken Dutch to get it.
Indeed they are. I have a five year old who is now old enough to choose his own films and series from a selection curated by us. A system like this would be fine for children of his age.
But 2 and 3? They are too young to choose their own media at all. Not because they can't, but because they can't judge the impact. For toddlers you really want to be the one in control about what they watch (and that horrible Bing can die in a tragic bunny bonfire).
The Lion King, Wall-E? That's just overloading them at that age (and both are rated 6+ in the Netherlands). You can start with those at 5 or so depending on the child, or later if you've noticed them reacting too intensely to films rated 6+. For now? Stick with shorts suitable for their age, and move on to films (like Ghibli's Ponyo) at 4 or 5 as a special treat.
Autonomy is all fine and well, but screens have an enormous impact on developing children. This is a really cool project, but you might want to reflect on how their brains are developing and what you as a parent can do to guide them.