Working and EU travel on a Swedish work-permit based residence permit.

I am assisting a person, currently in Asia, who has got a work contract with a Swedish company who will be sponsoring him for a job in Sweden.

I just wanted to post questions here to help him and me understand a few details about the Swedish work-permit based residence permit.

Am I correct in understanding that "work permit" is the legal status of the person and "residence permit" is the physical card that denotes that status?

Can he travel across the Schengen Zone carrying both his national passport (as proof of identity and as a travel document) and residence permit (to show his status as being resident in the Schengen Zone)?

Do the 90-days-in-180 rule apply to him as well, given that he is resident in the Schengen Zone?

Would he have more flexibility within the Nordic Passport Union countries, even as a Third-Country-National? That is to say, can he travel for more than 90 days out of 180 days within the Nordic Passport Union?

Apart from the field that he works in, he is also into martial arts and other such skills. Is he allowed to earn extra by providing coaching in fields outside the one that he has got the work permit for? Or is he restricted to the field that he is being sponsored for?

What are the advantages of an EU Blue Card over a work permit (he meets the requirements for both)?