The live rocks are adequate biological filtration. You can keep the HOB
filter for mechanical filtration, but you will run out of room in the back of the tank after you add the Aquafuge and HOB
skimmer. Its ok not to have the HOB
filter and do water changes for mechanical filtration. If you do enough water changes, then you really do not need to add any supplements reef tanks. Water changes restore all the used up minerals and whatever else corals need to survive in most tanks. Nevertheless, test regularly and consider supplements or other options as needed to fill the "essentials".
The powerhead is decent for water movement. More is better though.