Disclaimer: highly opinionated post, feel free to ignore.
BEEP BEEP BEEP WHOOGA WHOOGA WHOOGA
HTML is IMHO a terrible, no good, very bad choice for a transfer language. It’s hard to parse. It’s inefficient to store and query. You will be tempted to try to shoehorn it into your templates using innerHTML. Then you will discover that innerHTML doesn’t do what you want it to, and you’ll post a question here asking why links in it don’t work or something.
Your life will be much easier if you restrict yourself to structured data formats for transfer within your app and its network backend friends. The absolute best thing would be a language that is easily serializable to JSON, because it is braindead easy to work with JSON in web apps. Barring that, if you want to work with something like Markdown, see this post.
Even if you’re scraping web pages, put some intelligence into the scraper to the point where it can spit out something more manageable than HTML.
I wouldn’t keep both of these, because it’s just too conducive to spawning bugs that happen when they’re out of sync. Pick one or the other. Also, it’s not idiomatic to prefix types with I.