I used 2 FQs and mixed the prints for the flap and straps on each. I also made my pieces smaller so I could get 4 (actually, could have probably made 6) out of the 2 FQs. My base pieces were more like 5.25x8.5. I just folded the FQ and cut it into fourths and then measured the finished piece, used my proportion wheel and downsized the straps.
Topstitch the straps down both edges to give them some stability, that way they won't flop around.
I also cut a sturdy piece of cardboard for the bottom of the cushion so it stands nice and flat and doesn't wobble. And I didn't use fusible fleece, I just cut a piece of cotton batting. I wouldn't use anything fusible in a pincushion that I would stick pins through, don't want to gunk up my pins.
For the flap, I just measured the 'bag' when I made it and cut two rectangular pieces of fabric, sewed them right sides together and then pinned a piece of felt to the top of the bag and the flap on top and the handles on top of that. She didn't use a facing to turn inside, but after making the first one with out, I just cut a scrap 2" strip of fabric that I was going to use to hide the stuffing and added that around the top before I stitched.
I tried to make the first flap hae rounded edges, but it just didn't work out for me. If you want to do this, cut it a bit larger than you think you're going to need. (I cut mine to the width of the front of the bag and came out not wide enough)
Once I sewed all the way around, I turned all that inside and edge stitched all around the top (and over the flap) to hold it all in nicely in place.
I used a scrap of a third fabric to cover the stuffing. I tried using the fabrics in the pincushion but it just didn't look right, The contrasting fabric just seemed to work better. And I did use a glue gun, but I used fabric glue in it. Fabric gluesticks melt to be more sticky and pliable. You can reposition and a very little goes a long way, so if you can find them, use them.
Have fun. My online group is making a different pincushion each month, and I've got some patterns I want to try on my own, so check back for photos as I complete them (which will mostly be after I finish the Guild challenge quilts....so April or so will begin Pincushion Frenzy.