Well, that was fast!! Good for you
Mitch for getting right at it!
Yes, FMQing is a long slow learning curve, and sometimes you feel as though it is two steps forward and three back, but with persistence you will figure it out! I have a notebook at my machine and I keep notes with each project, so I can emulate it later .... kind of thread, needle size and type, setting adjustments, batting used, etc. At a time like this, then you can go back to what worked. Or can see if there is something different.
The seam issue could be partly the drag issue. Also might be the needle you are using. There are a lot of different types of needles, and some find one type works better than the other.
As for the drag problem .... some build up the area around it, to give a larger table than the extension gives. Another thing to check, when you are FMQing, is the quilt on top of your table that the machine is on? Or hanging off the edge, towards the floor? If so, that can create a whole lot more drag, than if it is all scrunched up on top of the table, and you only have that 4" or so, of drag from the rise from that surface to the extension table.
Keep smiling Mitch! .... and cheer yourself along, that you know you can do it, if you keep at it!