With Juno/Pantheon Files v4.2.0:
In brief, I try to right-click multiple files to open with a preferred application, but that application isn't available if at least one of the preferred applications doesn't match.
In detail, preferred application extensions from multiple file selections (either marquee, check mark, shift-select, or ctrl-select) display the default application I've set for them at the top of the right-click pop-up menu, called "Open in…", followed below by sub-menu "Open with…" alternatives, but only if the default applications are a common preferred application.
If at least one of the multi-select file defaults is an alternative application, the preferred application I'm looking for isn't available at the "Open in…" slot or "Open with…" alternatives. Selecting any multi-select file singly, my preferred application is available inside either menu item.
With mulitple selections, the default Elementary application is available, but I see no reason Files would cull my preferred application while the Elementary default remains.
Is it normal for a combination of default applications to strip my menu?