What is the correct terminology for games like Final Fantasy (the early ones)

For the most part, RPG is the main classification. Some might also opt to say JRPG, or "Japanese RPG", meaning to distinguish this narrative-style from the more open-ended style of western RPGs such as Fallout.

Past that, it's pretty rough and there probably isn't a specific terminology. Genres are kinda broad by nature and it's by tagging a ton of extra labels on top of it that specificity is found. For example, the descriptors for the early Final Fantasy games will generally be "turn based" and "menu driven" party combat in an "overworld exploration" RPG.

If you want to narrow it down to the essence specifically of the full combination brought by Final Fantasy, I think there isn't really any general term so much as a "likening". That is, you'd call a game of similar substance as "a turn-based menu-driven RPG like the Final Fantasy series". This is kinda like how Etrian Odyssey had been marketed as an "old-fashioned first-person dungeon RPG like the Wizardry games". First-person dungeon RPG isn't the most descriptive, but it kinda fits those games to a T and "Wizardry-like" never really took off quite like "roguelike" did.

Past this, there really isn't a unique terminology for these games. Early SaGa games, early Final Fantasy, Dragon Quest... RPG has pretty much been the identifying term for them since very early on, and little has changed in that department.

The name used in the industry is Role-Playing game, but they are commonly referred to as "Japanese Roleplaying Games" (JRPG) within the gaming community. Eastern RPG is another commonly used term, but it's not as widespread as JRPG.

Honestly, a more specific term doesn't exist besides JRPG. A lot of gaming personas and shows have mentioned that fundamentally our game genres are not of any use. I could write out the entire the reasoning and logic but I'm not nearly qualified enough. Which is why it's a good thing someone else has done this already:

http://penny-arcade.com/patv/episode/western-japanese-rpgs-part-1

In regards to this question I'd say the most relevant part is pointing out how our genre definitions are incorrect (Around 2:30 minutes). The reasoning is that we define based on systems and surface elements and core reasons for playing.

So honestly, the answer to your question is, there isn't really a current term for those exact sorts of games. We can list aspects but the whole or niche they play is difficult to define. At the moment I would suggest turning your search into "16 Bit JRPGs" if you want to catch a lot of them.