Don't have any experience with that specific study but I myself tried to plan my studies and it did'nt really work out how I thought it would....
You always have to start with a Bsc (Bachelor) so you should'nt worry about a Msc yet. How can you study Public Relations in highschool btw?, assuming the Belgian system is about the same as the Dutch.
Don't overthink the job opportunities, no-one can predict what the economy will look like 3 or 4-5 years (depending on how long your Msc would take). Choosing a diverse Bsc is always a good thing, don't put all your eggs in one basket, assisant management sounds like you could work anywhere so I guess youre good
. With your Msc you can always finetune the direction you'd like to go in, I got a Bsc Industrial Design and am currently doing a Msc in Innovation Sciences, the two don't really have much in common.
Salary guidelines are also something you should'nt worry about too much, if it's about what you're looking for it's ok, in the end it always comes down to how good you are.
To make a long story short: pick a broad study in the field you like and specify with your Msc, by that time you might have figured out what you want