You can keep fish only with a standard flourescent light fixture and the bubbler isnt needed in salt water.
The filter will be fine too and a skimmer is optional as long as you do weekly water changes. Some will say a skimemr is a must but for your tank size you are on the borderline of needing one in my opinion.
You would just need sand and some live rock ad you could be set to go. You will want to use ro
water though so see if your store has that. A refractometer is also needed to check salinity, about $30 on ebay for that. And just get a good test kit, like an API liquid saltwater master kit for your cycling.
Thats about it really.