Here are some more things to consider at #8.
re: Tristan Wirfs. I am fairly comfortable saying that most on this board, given his availability, would be interested in signing Brandon Scherff in free agency. What needs to be considered is that Scherff was drafted #5 overall to be a RT for the Redskins. 5 years later, people are willing to pay him 12mil+ to be a RG. Even if Wirfs fails at RT (which I don't believe he will) he has the ability to kick inside to RG and be a difference maker there as well. His paths to abject failure are fairly limited and he protects the most valuable piece of our franchise. Wirfs at 8 is 2020.
Also...while taking a RT in round 1 has not traditionally been a move that was considered smart, take into account that Lane Johnson, Mike McGlinchy, Jack Conklin, Bryan Bulaga, and Ryan Ramczyk are all RTs who were drafted in round 1 and have had pretty solid careers so far.
When considering Derrick Brown...the best interior linemen in the league play between 65% and 75% of defensive snaps. The best OL, ILB, and CB all play 90%+. When valuing a player at #8, are you prepared to lose out on 15% to 20% of on field snaps because of the position played?
In terms of dollars saved, currently there are 15 players at the EDGE designation whose contracts average over 14mil per year. Other positional considerations, 8 DT/DE(3-4), 4 ILB/OLB(4-3), 5 CBs, and 6 OL. Hitting on a first round pass rusher and/or DL player provides you the best rookie contract value out of these groups.