Is it possible to post a question in 2 places at the same time?

You can have the same question OPEN in 2 categories at once, if both categories are appropriate, but you have to submit them separately. And spend 5 points to ask, each time.

There's no way to submit a single question to multiple categories at once.

yes you can

you will have to ask it twice and to be on the safe side slightly reword it

No.