Is it possible to embed a Flash Player in wordpress (inline)

Yeah, I think you should think of it this way.  Flash Player is a language runtime, sort of like Java.  We're more like an operating system than a video player.  We process code generated by developers, and do the low-level work of interpreting it and rendering pixels to the screen.  Developers can use Flash to build video players, but Flash itself is not a video player.

When you factor in the wide variety of things that people use to browse the web in 2017 -- all of the various phones, tablets, TVs, netbooks, notebooks, laptops, desktops, etc... writing a single video player that does that well on all of those targets is really hard.  Then there's the question of whether or not you want to get paid for that work, which introduces yet more complexity.

The good news is that there are a bunch of companies that specialize in making this easy.  If you're trying to get paid, consulting with a professional with expertise in web publishing is probably going to save you a lot of time and effort.  They're going to know the landscape, and can help you choose a service that best fits your needs and goals.  Alternatively, any of the major consumer-oriented streaming platforms like YouTube and Vimeo are really probably going to get you the best outcome.  I believe that Vimeo lets you sell video through their platform, and YouTube lets you monetize with commercials.

There *are* also a bunch of developers that sell Flash-oriented video players and things if you really want to host the video yourself, but it's a non-trivial undertaking, and without expertise or a real business driver to do that, I think you're going to get a better overall outcome with far less effort by using one of the well-established platforms.

I branched your post to a new topic as it was not related to the topic you posted to.

Flash Player is installed on the client, not the server.  You can include code in your site to detect the presence of Flash and prompt users to download and install it