Regarding your question about adding live rock, you don't want to add any substantial amount after your initial setup because die-off from the live rock can cause your tank to cycle again which can be very hard on your fish. Small additions shouldn't hurt if you have a large tank (50 gallon +), though you'd be better to cure them in a separate container for a few weeks before adding them. You'll want to look up "curing live rock" if you're unfamiliar with the process. This also lets you look for stragglers and hitch-hikers.
I would add as much live rock as you can at the start, deal with the cycle, and then enjoy.
I've never heard of a "need" to match live rock from the area that the fish originates, especially for cultured fish that have never been in the wild. Certain fish definitely like certain characteristics of rock but that's more down to the individual piece that the origination point of the rock. For example, my flame hawks love tons of holes to hide and peek from, but they have no clue that some of my rock is fiji, some of it is texas holey limestone, etc.