Not loving the color combo here.
I would probably stick with the colors in the pattern, myself. But I was just using what I had.... and it was Caron Simply Soft instead of the suggested Red Heart. The only issue with that was that the chains I made for the green X in the middle were too long... they're pulled tight from the back for the picture, but I would have to adjust the length of the chain if I were to use Caron for the real afghan. It never says how big your finished square should be, just the first 2 rows. But the finished afghan is supposed to be 48" wide with 5 squares across, so I'm going to go with approximately 9 inches. My square is 7", using thinner yarn and smaller hook. It took me about 2 hours, total.
I would say that it's a pretty intimidating pattern jumping in, but once you get the hang of what's going on, you could probably do it in your sleep after the first few squares. But it's impressive-looking, for sure.