If you get a trust, that makes it easier and safer too. Not an LLC, not an internet trust, not a regular property trust. An NFA trust. Just make sure to find a local attorney familiar with NFA trusts. In WA, I went to NW Gun Law Group. You can have your wife as a trustee too if you want, she will be able to buy and sell items from the trust just like you will, and add and remove beneficiaries (people you don't mind firing your weapon) as you please, and if they are not legal to possess it and get caught, then you don't get in trouble. The trust also eliminates needing the fingerprints, pictures and CLEO signature. Just a great idea all around, I wouldn't get into this without one even if they did away with the signature and other hassles.
As for the suppressor, I'm doing the same build. I went with the AAC SDN6, they did after all design that round and used that suppressor to do it. They claim it is quieter than an MP5SD! So that is the one I'm waiting on right now. Nice thing is I'll be able to use it on several rifles, including an FAL and Grendel, though it will work with the BLK the best I'm positive. Those Blackout flash hider mounts are expensive, but they also WORK. Never seen a flash hider that actually works that well, it lives up to the name "Blackout". Would be worth the price still if it wasn't a mount and you needed a good flash hider or used night vision for whatever reason.
Good luck. And yeah, you should read up on the stuff. There are lots of threads in this NFA forum about trusts, how to do it, etc.