If it were up to me, I'd release it across four episodes, titled "Birth," "Life," "Death," and "Synthesis," respectively. Each would culminate with a final boss fight against the respective incarnation of Jenova. These moments are also, in my opinion, the most natural and climatic act breaks for the story, and so I think this implementation is actually pretty likely.
The only question for me is how they would handle the first episode. I can imagine two likely scenarios: The first, and my gut instinct, is that they would rework the first episode to take place entirely within Midgar, obviously elaborated. In this case, I suspect that the extended Nibelheim Incident flashback in Kalm will be broken up into shorter segments and drip fed to the player over the course of the first episode, and the first encounter with Sephiroth and Jenova will occur within Midgar, facilitating the party's escape from Midgar as Sephiroth kills a platoon of pursuing Shinra MPs or somesuch, instead of the cargo ship's crew. I feel that this would probably actually work better narratively, and would be a novel way to retell the story without significantly changing it.
The other option, and what I think I would actually prefer but is far less likely due to the work involved, would be for Square to exclusively market the first episode as if it would take place entirely within Midgar, showing only footage, screenshots, assets, and characters from that section of the game, and then reveal the entire surrounding region as a surprise open world environment that opens up near the end of the episode. Assuming no journalists broke the embargo and the game didn't leak, this could be really a big deal that would generate a lot of buzz. And it's the only way they could ever really recreate the experience of leaving Midgar for the first time and being blown away by the scope of the world when you reach the world map.
In the latter case, I'm not sure that actually implementing Junon would be a reasonable expectation, even though it could likely reuse a lot of assets from Midgar. A more likely stopping point, then, might be at somewhere around the Mithril Mine, thus closing off the rest of the Eastern Continent.
Anyway, beyond that point, I think that the remaining three episodes would flow quite naturally, with new forms of transportation becoming available in each, allowing you to freely explore increasingly large sections of the world. When all is said and done, release the ultimate edition bundle. Maybe call it something like Final Fantasy VII Remake: Episode Collection?
Beyond that, after having spent years recreating Gaia and the thousands upon thousands of assets necessary for Remake, it would be an absolute mistake not to leverage it for new content. At that point I think remaking the rest of the Compilation in the Remake engine would probably be easier and safer investments than moving on to FFXVI or whatever other major title they're going to tackle next.
Remakes of Crisis Core and Before Crisis seem like easy enough options to me, maybe even a single reimagining that combines both into a single game. Maybe even do a fully playable reimagining of Advent Children. They could even continue the episodic formula and treat them as new seasons.