I really do not see how any of these are so far fetched when they’re based on solid indicators. Especially Knuckles. Plenty of others believe this. It’s not just me. Some think Robotnik will use the quill to make Metal Sonic. Seems like a good guess but that’s more of an assumption when we have not even seen Badniks. It’s true Echidnas were not originally planned but the Mushroom place was. Imo such a location in this particular movie along with Robotnik getting trapped there is just hard to ignore and call filler. If it ends up really different and those of us are wrong...well it’s fine but it would be a heck of a turnaround considering where things are pointing at moment.