Is this possible?

That should already be possible.

In the upgrade planner, the red (long) inserter doesn't show up in the list. In the Bob's mods group, I am only using this one and the greenhouse mod plus Bob's library. Also using the miniloader mod. Don't know what else could be causing this.
Thanks.

If you're only using this mod, and not any of my others that change inserters, then longhanded inserter is on it's own fast-replace group, and wouldn't be available in fast replace.

also, because the Long reach is set by the entity prototype, not by a script, then when the migration did happen (if it were allowed) the range would be lost.

It's a fairly complex interaction, but basically, ranges are only kept if set by script, not the prototype's default.