I start by asking myself who I think is a virtual lock to be gone by #29. This is how I see it:
QB (2): Trubisky and Watson
RB (2): Fournette and McCaffrey
WR(2): Davis and Williams
TE (2): Howard and Njoku
OL (3): Bolles, Lamp, and Ramczyk
DL (1): Allen
EDGE (2): Garrett and Barnett
LB (2): Foster and Red****
CB (3): Lattimore, Conley, and Humphrey
S (2): Hooker and Adams
That's 21 players. So now of the players remaining, who do you like? For me:
QB (0)
RB (1): Kamara
WR (1): Ross
TE (0)
OL (0)
DL (1): McDowell
EDGE (4): Watt, Bowser, Willis, and Harris
LB (1): Davis
CB (3): White, King, and Awuzie
S (1): Melifonwu
So that's 12 more guys. So of the 12, who matches a need? I would qualify CB, Edge, RB, and OL as the primary needs.
That leaves 9 guys: Tre White, Kevin King, Chidobe Awuzie, Malik McDowell (counting him even though he's DL because of pass rush), Watt, Bowser, Willis, Harris, and Kamara.
It looks most likely to me that the marriage of value and need will come at edge rusher, or potentially McDowell if the FO believes that they can get him going in the right direction with the culture of their lockerroom.
Further supporting this likelihood is the fact that Thompson has only ever spent 4 picks on non-LOS players: Rodgers, Hawk, HHCD, and Randall.
DL and Edge are his most drafted positions in round one.