The hurdles for people new to roleplaying
Roleplaying has a few things that are rather unique that take time for non-roleplayers to pick up. A lot of your early play is them learning to navigate these ideas:
There is no set of moves, if you can imagine a plausible action, it can happen
Players can and should ask for more information/clarification during play about anything they see/encounter
Gameplay is not tied to a board, set of cards, or other physical object
Character motivations can be a primary driver of what to do in play
How to speak in character, how to shift between in character/out of character talk at the table, etc.
You'll notice that these are system agnostic—it doesn't matter what edition of D&D or which roleplaying game you're dealing with, these are all concerns. I list these for a simple reason—they're actually a lot to take in, so if you stack too much other complicated stuff on top of it, it just makes the experience that much more confusing for new players.
D&D specific hurdles
D&D in all of its editions doesn't do a lot to particularly support, or work against roleplaying—it really comes down to what you want to focus on in play. So it's worth noting at least in that regard, there's only two measures by which you can decide which edition works best/worst for you: complexity (for the reasons outlined above) and lethality.
I bring up lethality because even though you have a roleplay-heavy plan, the fact is when you do have violence, if the game has high lethality, the players don't have a lot of margin for error and learning before they lose their characters to death. That becomes even more frustrating if they've invested a lot into the character's personality and background.
With all that in mind, I'd say consider either one of the Basic D&Ds from the 80s or a free D&D clone / "Old School Renaissance" game (like Swords and Wizardry White Box, for example, for the simplicity of the rules, but start the characters off at something like 4th or 5th level to give them some hitpoint buffer from getting instantly wiped when combat rolls out. Hand out some basic equipment kits and don't make players have to do a lot of equipment choosing and you're good to go.
Play a bit, and after the players get comfortable with how basics of roleplaying work, move up to whatever D&D rules best fit your group's desires and they can better navigate the rules complexity without having to do that while figuring out roleplaying itself.