There's no way this is appropriate for Disney+. The reason the Fox shows are on Hulu is more than just being Fox. It's because the content is not remotely comparable to what's on Disney+.
Even in The Mandalorian, you could see the parts where another network wouldn't have tamed it down quite as much (not killing off the monster cast in the heist episode is atypical compared to other monster heist trope episodes I've seen and you have to squint to see the romance in the closest thing to a potential love interest episode). The likes of PotC and the SW saga films are probably the top end of the PG-13 content allowed on that service. The content in those is definitely well above PG Mando, which I assume is the most mature original series Disney+ has made so far. Eunuch jokes probably go over the kiddos' heads, but there are quite a few deaths/amputations/crispy-fried!Anakin/creepy skeletons in those.
Is Indiana Jones on there with the Lucasfilm properties? If so, the underaged-Marion (ahem, that backstory was her only being 15--Young Indy was actually going to show the Abner fallout in an unproduced episode, though Carrie Fisher did write the episode where Indy lost his virginity to Mata Hari) and father-and-son-sleeping-with-a-Nazi conversations probably are the most risqué content on Disney+, not to mention the still-beating heart being ripped out (still censored in the UK) and faces melting off. Indy also curses a bit ("Hahaha, son of a b..."). Raiders (a wall of fire was placed to obscure Belloq's head exploding) and Temple (along with Gremlins, helped create PG-13 in the first place) were close to being R-rated.
Buffy season 6 is definitely a problem unless somebody at Disney+ is thinking they'll get more subscribers if they start packing the service with Fox shows for the teens and adults. They might want to partition it off. Or better yet, just take Hulu international and combine it into the Disney+ package in HD without commercials. I can imagine it's limiting their subscriber pool when families are looking to only purchase so many streaming services, see the limited content level on Disney+ and think their kids will be just fine with the kiddie movie sections on Netflix, Hulu and Prime.
Apparently, even an attempted Lizzie McGuire (!) revival was too adult for Disney+. Somebody at Disney+ is seriously confused if an old Disney Channel show revival was thought to be too mature, but then they want to bring over Buffy (or maybe want a toned-down reboot for Disney+?). I can only assume this person who added Buffy for consideration hasn't seen it and just saw it as a popular request by people who don't get Hulu.
With that in mind, no way in hell is Buffy/Angel getting on there without being hacked to itty-bitty, unwatchable pieces. They might be able to air the high school seasons at most once it's been edited down into Goosebumps. LOL.
If Mando is an indication for their exclusive new shows and if somebody at Disney is thinking of rebooting Buffy exclusively for Disney+, it's probably not going to have the same content level as the WB's, much less UPN's, Buffy/Angel. They might allow some of the campy, relatively bloodless violence (Mando has plenty of explosions and blaster fire), but you can see where deaths and romance are minimized compared to the average network show or even some of the blockbuster PG-13 films Disney started allowing to be made under their own name starting with PotC instead of Touchstone, etc... Back in the day, The Nightmare Before Christmas was released on the Touchstone label due to its content, only to be retroactively embraced all over the Disney parks. Doctor Who is famously watched by children (obviously not up for consideration), but I'd say it would be pushing it for Disney+, content level-wise (see the habit of killing off most of the guest cast, some of the revival's innuendo and some of the horror stuff). Mando is less than that, by comparison.
If Indiana Jones is there, I think they could just about get away with everything but the UPN seasons. Where the Wild Things Are is an earlier episode that might be pushing things sexually. The high school seasons are safer, but still loaded with innuendo and certain subjects.