Hi,
I sprout some whole grains.. I like the idea of complete living food, trying to mimic nature.  I do grind some of the grains I use, and also offer a dry ground complete mix of the grains.  Lets just say it is a major commitment of time and energy.  But worth it to me.
I would say grinding only has two positives. 
1. You can get the birds to eat ever thing and not just pick out what they like.
2. You can just dump it in a feeder, so convenience sake..
Yes Organic grains will be non GMO..  The two biggies in the GMO world are soy and corn.  I use everything organic but the BOSS because I can not find organic BOSS that does not cost a fortune. 
Soy..... Lots and lots of opinion on it.  Soy is the #1 protein source in animal feeds in America.. Also soy is added to many processed human foods... Some people such as my self are opposed to the mono cropping practices of corn and soy, and feel we get way to much of it in our diets, and that is why we choose to not use it.  Some have concerns that Soy causes hormonal imbalances and is bad because of that..  (Keep in mind Asian cultures have been consuming soy for a long time, but that soy is generally FERMENTED.)
Instead of Soy I use field peas... They were popular as a feed stuff in days gone by....
So I personally am soy free...
ON