Actually, there are no "favorites" in Firefox - they are bookmarks (and it's called the bookmarks tool bar). Very handy to simply click on one, a new tab opens automatically (that is how I have it set) and the page loads....

And, the tabs do not take up the entire width of the open window, which is another absurdity and they are easier to close as well. I like bookmarks and I like tabs (especially with ASC - without them, I'd never do anything here, LOL). Apparently Safari considers bookmarks and favorites as separate entities so to speak and Apple has decided that everyone must have Favorites.
So, back to the iPad - you're saying that deleting them is the only way? I'd like to have them as bookmarks, nothing else. They are direct links to the European TV movies/shows I watch and last night, I wanted to switch from my just watched channel to another, which is what I struggled with. I finally figured out tapping the + sign will get me another tab, but it showed favorites which I did not want. Apparently, there is no way to get an empty startup page? I will need to play around with that more later today.
FWIW, I usually use Atomic Lite on the iPad - much easier to worth with tabs and bookmarks (no favorites there either), but some of the European channels respond better (quicker video loading/no choppy or pixelated playing, etc) when using Safari for whatever reason.