I'm not a seasoned vet but I think you could add two fish at first then based on your biofilter catching up and your parameters staying stable, wait a botu 2 weeks and add one or two.
You also have to think of the order of the particular fish. tangs should all be introduced at once, so if you wanted 3 youd have to add them all, BUT I think that would be fine.
I want anthias', but it says its best to introduce them all at once. I wouldnt normally add 4 or 5 fish at a time but theres occasion when you do.
I thinkit;s best to start of with the more mellow fish and then add the most aggressive last.
just my thoughts, hope it helped