Learn English – waste money into or on

This website lists about two dozen three-word phrasal verbs. As I looked through the list, they all seemed "inseparable" to me.

However, have said that, I think there is some wiggle room for a few of these, due to the flexibility of prepositions.

For example, consider talk back to. That form may be the preferred version, but one might see talk back at used instead:

When you're in school, don't talk back at your teacher.

Also, there are times when one of the three words can be cut out altogether, resulting in the use a two-word phrasal verb instead. For example, the website lists check up on as a phrasal verb meaning "examine" or "investigate," with the example:

The boys promised to check up on the condition of the summer house from time to time.

I think one could remove the up and retain the same general meaning:

The boys promised to check on the condition of the summer house from time to time.

As for your example, the preposition could probably changed from on to with, and the result would be a more common way of writing it:

Unfortunately, I wasn't able to keep up with the news while I was away on vacation.

To

give a dinner for

implies it is an honorary dinner, even in your first example.

...gave a dinner for the Shah ( in honour of )
...gave a dinner in honour of the Shah ( obvious meaning )
...had dinner with the Shah ( maybe just grabbed a bite to eat )

Doing something in honour of someone, is to do something for someone with a feeling of respect. To do something for someone does not necessarily mean the feeling of respect is involved.

In your example, giving a dinner to someone is to physically hand dinner over to them. Giving a dinner for someone means you are celebrating something and allows you to participate with them.