By the way is there a way I can find out which/how many Wild Fragments I've used? I still need one to open the Archylte Steppe gate but I've no idea where I can find one because I didn't keep track of which ones I've already used.
There is a very real possibility you have missed the one in Archylte Steppe. The area to the far West has one on a small ledge over the cliff. If you pull up the Archylte Steppe map, it's all the way to the West/left of the map. You have to go to the cliff and walk the perimeter, looking down as you do. You'll see a little area with a floating artefact on it. Throw Mog down there and there you go. I believe the cliff is closer to the North part of the cliff but don't quote me on that.
I bring this particular one up because it's the one I missed. I scoured the guides and, for whatever reason, thought I had gotten this one. If this isn't one you're missing, check this guide.