I'm cautious about posting to this, and may be a bit biased, I've read a lot about O-Line and this my 2 cents.
People seem to have forgot about Dallas Hart, he was the starting center and was lost pre season to a knee injury, if all went well with his knee I would expect him to be the starting Center next year as a Sr.. I would also expect Angel Villanueva to be the starting LG also a Sr.
So let's talk about the other 3 spots.
LT - I expect Sean to push Conlan for starting position (my bias) and FYI Sean is nasty on the field. And if not Conlan will only get better.
RG - I think Tyler Ganoung has a great chance to start (also my bias as he has become a good friend of Seans) FYI Tyler has a nasty streak also. I just can't see keeping Sirmon there as its not his natural position. There is also Cole Sain that has a nasty streak in him. This could be the only spot a JC transfer could take.
RT- I can't see any reason why Colton wouldn't continue to get better and keep this spot.
I won't get into a 2 deep, too much up for grabs there.
The rest:
not sure why everyone is taking about JC or FBS drop downs, at best a JC player would be a Sophomore, so what spot is he going to take? you only take JC if they are going to start. Why on earth would a FBS grad go play in the FCS? never going to happen, they will go to another FBS school. I guess there could some frustrated FBS guy that isn't getting any play time that would be tempted, but how easy is it to find that guy? and why isn't he playing?
Holding, you can grab pads inside the shoulders all day long and it isn't going to get called unless the defender tries to pull away and you don't let go.
What I didn't see from the O-Line this year was some nastiness, pancake a guy and then get on top of him, dominate a guy and then stand over him and let him know you own him...... Sean turned that switch on his Senior year in HS, nothing like taking the "will to play" out of a defender...
Germer is a good coach and I think the line will be better next year (again my bias)