@MeganB, @tracyS, @Nhaama have all given you some wonderful information.
I think I can help by expanding on some their answers as well as @Mystique
My first question is if you feel pulled or anything for the Triple Goddess?
Something that you should understand is that when first starting if you choose or a deity chooses to work with you, then start there. If you feel drawn to one than go ahead, as far as the Triple Goddess “going” with the Horned God… My best advice is if you don’t feel drawn to the “Horned God”, that’s okay. Making a connection with the Triple Goddess by herself is just fine. It may be that the Horned God will come to you at a later time or you can just work with The Triple Goddess.
Hekate I believe is recognized as a form of a Triple Goddess. Although I’m not entirely sure that if it’s Maiden, Mother, Crone. The Maiden, Mother, Crone is more of a neo-pagan type of association.
Hades I know @Amaris_Bane has worked or does with him. I think we have some information on him.
→ Greek & Roman Deities Master Post
You seem to be leaning toward Greek and Roman mythology and practice. So the MasterPost may help you with at least the 2 from their pantheon.
→ The Triple Goddess - Maiden, Mother, Crone
→ Triple Goddess Day & Offerings
→ Triple Goddess Incense 
When I first started I was drawn to Brighid after a couple of months. About a year later I was drawn to The Morrigan. Both of them are from the same tribe in Irish mythology and pagan practices. The both have similar, if not the same aspects but are both Goddesses with a Triple aspect. Except that aspect is that Brighid & The Morrigan can be worked with as a singular deity or one of three sisters. In the case of Brighid, she has two sisters also named Brighid. The Morrigan is one of three completely different sisters or as a singular deity. They don’t hold the Maiden, Mother, Crone aspects of when you typically hear Triple Goddess relating to Maiden, Mother, Crone. (Sorry if that is word sald at the end there, I’m going to quit while I’m ahead on that one 
)
Your practice is your practice, so whoever you choose to work with or want to work with you is completely up to you. It’s perfectly fine to ask for assistance when working a ritual or spell that is from an outside deity or another deity not related to each other. Whoever is best for the spell or ritual at hand as @Mystique mentioned that she does in her practice.