There's only 89mm difference between the two widths - I'd guess that isn't enough room to have both on the same track.

This is how it looks (Galati, Romania):

https://greatnews.ro/wp-content/uploads/2022/07/linia-ferata...

I can only imagine what the switches look like.

I believe something like this: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2F8...

There's already some dual-gauge track on the border with Sweden in Haparanda/Tornio[1].

[1]: https://maps.app.goo.gl/qjRZTz3K9sbVYpDX6

I very much doubt it. Change to dual-gauge requires replacing the sleepers, and if they do the very hard work of replacing the sleepers, then why keep broad gauge?

Maybe they would choose to downgrade a single track where there's two, and half of each station's lines, but that would make it very difficult to schedule trains in both directions on a single track. So, they're probably not going to do that either.

The only feasible way to do this (based on preliminary reports) is to simply build new track next to old track in the same right-of-way. The transition period would last decades.