Im a young reefer too, so its nice to see im not alone. Its a great hobby.
A clownfish pair would do nicely, as for Dory a yellowtail damsel could fare as a far better substitute than a super active hippo tang. Although personally I am not a huge fan of damsels as each fish has its own personality, and you would be taking chances. EDIT: Forgot to mention that certain damsels can be nasty little buggers, think of male geckos together but some damsels see all other fish as males. Theres actually a species of damsel called the Blue Devil, beautiful, but a devil. Yellowtail damsels are the slightly more mellow species, but there could be that ugly duckling that deserves the name of a devil
As said by cgthebeast, automated systems do not work best, automatic feeders are unreliable. Just saying, most fish wont accept flakes and pellets at first, so I always have an arsenal of frozen and other foods ready like; Mysis Shrimp, Krill, some seaweed, and seafood mix you can buy at grocery stores. Variety is key for success, and Mysis Shrimp is my personal favourite for picky eaters.
Things you will need,since you said cost isnt much of a problem, I will just point out some of the slightly better equipment for better success(Please be aware I might forget a few things)
-Aquarium (Obviously lol)
-Live Rock(1 pound per gallon, preferably 2)
-Marine Salt (Not the freshwater aquarium salt used for treating ill fish)
-Refractometer or Hydrometer (Used to measure salinity. Hydro is cheaper but not as accurate, Refracto will cost you about 50$ but is one of the best investments and really fun to use ;3)
-Powerheads(Basically a pump used to make circulation, to create currents essentially)
-Lights(If she is only interested in keeping fish then any lighting will be fine, however if shes interested in keeping corals etc. go with High Output lighting.
-Buckets(Any aquarium keepers best friend)
-Reverse Osmosis system (Tap water contains so many things that de-chlorinator cant just take out that can just cause havoc in your aquarium, an RO
system removes those elements.RO
system means less algae pretty much, but other factors take place too)
-Test kits(I usually dont recommend master test kits, some tests you might only use once, but for a new aquarium and beginner, knock yourself out)
-PATIENCE!!! While freshwater systems dont require as much patience, saltwater systems DO. Personally I wait 3 months before adding any fish, but it varies from system to system, I think 2 months could be acceptable. Honestly just looking at my water chemistry amuses me.
Things that are sort of optional (Some are debatable)
-Protein skimmer (I HIGHLY recommend one, its not like you HAVE to have one, its just that it works wonders by taking out small particles that a normal filter couldnt take out.)
-Filter(Live Rock established with bacteria will do biological filtration, but a filter is totally optional as long as your bioload is low, what some fish keepers have is a sump, far better than just a regular filter, although you should do more research about them)
Keeping things clean (What we call a Clean Up Crew or CUC)
Most CUCs are made up by invertebrates, not fish. I usually recommend at least Nassarius snails as they are basically like your cory catfish of the saltwater world, although slower and well, a snail. Other CUCs are really based on what you wanna do with your tank, and I cant recommend them until you decide if in the long run you want ONLY fish, or want to make a reef tank with corals. CUCs dont really add much to your bioload(or max fish count) but there are usually general rules of each type of invertebrate, it varies greatly but something important is to never add in CUCs en masse, algae wont always last forever, and once algae eaters lose their food, they will probably starve to death, or you have to feed them (Mind you that you got a CUC to take care of uneaten food or take care of algae, NOT an extra mouth to feed)
The inch of fish per gallon doesnt apply to saltwater, but you can read on other peoples similar sized setups (most likely 29 gallon setups,you might be able to add an extra fish compared to their setup and see how they fare) I actually would recommend getting a clownfish as your first fish, as they are super hardy and have lots of personality. After maybe 2 weeks to a month (its debatable, I usually wait a little more than a month) you can add another clownfish, but make sure you do research about adding another one as there are some points you need to make sure of. By the way, dont get an anemone. Theyre best for experienced keepers, and need really high lighting. Also, when they die, they smell TERRRRIBLEEEE. Your next fish could be a goby or something else, I never really kept a system around the 30 gallon mark.
There arent any submerged plants that Im aware or have seen in the hobby besides algae. There could be some, but I have 0 clue on them besides mangroves.
I can say I definitely missed on some points, made a few mistakes here and there, but this should give you a general idea of how things will work. Sorry that this is kind of long, just had some time ;P