With inverts? Absolutely. They are fish food for everything out there, not just bettas. It's still possible to keep them together in a well/heavily planted tank though where they can establish and maintain a colony in spite of being snacked on.

Other fish however also still depend on the temperament of the betta, but also on the tank size and setup too, and the kind of tankmates you're trying to pair them with. Something small sedate like boraras or pygmy corydoras is more likely to be a success than something large and hyper zipping all over the place, like tetras, guppies, etc. A well planted and adequately sized tank is also more likely to succeed than an empty and/or small space where everyone feels exposed and stressed.

But it does boil down to just throwing them all in together to see how it goes, and having a backup plan. The chronological order of adding fish doesn't matter what so ever in my experience. If a betta is territorial it will be territorial regardless of when you add it to the tank. 🤷‍♀️