I'd like to keep Waller in the 6'6 240 range. I think he's a little heavier than that right now, but his versatility is probably best preserved at 240. I don't think he has a true position, but I like him as a a matchup disaster, whether it's killing LBs in the seams or mossing guys outside the hashes. Unfortunately, he hasn't proven yet to be able to moss guys regularly.
Fullback is interesting to me. Lorenzo Taliaferro is the closest fit we have to the modern fullback in the mold of Mike Tolbert. He's already an ample pass blocker, and if you get him to 240, I think he'll be able to handle blocking many (but maybe not most) linebackers, and he'll demolish safeties. One thing I like about Tali is that he's more mobile than Juice which will make him a better blocker in the open field, and frankly, that's what we need a fullback to be 2017. A guy who can just crack that last defender, be it a backer or a safety, to spring the play. Juice wasn't the most agile fella, and he wasn't the best open field blocker because of it.
Now, Boyle I think can fill that traditional fullback role, but he's definitely a bit too tall and, well, slow, to be a fullback. Being a good fullback is dependent on getting to the landmark before your assignment does. A slow fullback means a linebacker blowing up your back for a two yard loss. With his height, too, he'll have no leverage -- which is crucial in the trenches.
The thing is that linebackers are getting faster and oftentimes smaller. I don't have data to prove it, but empirically, that seems to be the trend. Going off of that, Tali is my pick for fullback. He's a true triple threat as a blocker, runner, or receiver, and Boyle isn't. He's also much more athletic, and as defenders are increasingly more athletic, you need an athletic fullback to keep up. I do not support Buck Allen at fullback. Way too gifted as a runner to be used as a blocker.
On the line, Yanda at RG or LG, period, sorry. I think Alex Lewis will be fine at RT if it comes down to it.