Okay, as it turns out it was not hard at all to backport the latest matplotlib.animation module so it works in pythonista. Obviously, things which rely on ffmpeg are not going to work, but to_jshtml does work, since it works by saving a sequence of temporary files, then encoding those files and embedding into html, with some js code to decode and play. The results is an html string that can be passed to ui.webview.load_html().
You get this by first importing the package below in your code. Then ani.save would be replaced with to_jshtml and load_html.
See README
https://github.com/jsbain/pythonista_matplotlib_backports