I would build the OL in FA and DL in FA and early in the draft
The tough part is that free agency doesn't always align with needs. I am also more inclined to build a deeper roster through free agency to enable more flexibility through the draft. An example of this would be adding a player like Stephen Weatherly from Minnesota. Pay him a bit above the market rate, give him a chance to compete for a starting spot, and you have a low invested cost if he can't handle it.
Let's look at our depth chart heading into next year on the lines.
OL
1-Justin Pugh - OG
2-Mason Cole )G/C
3-JR Sweezy - OG
4-Lamont Gaillard - C/OG
5-Joshua Miles - OT
6-
7-
8-
Three open spots. Our free agents are...
AQ Shipley
Max Garcia
DJ Humphries
Marcus Gilbert
Justin Murray (RFA)
DL
1-Corey Peters - DT
2-Michael Dogbe - DE
3-Zach Allen - DE
4-
5-
6-
7-
Four open spots. Our free agents are...
Rodney Gunter
Clinton McDonald
Jonathan Bullard
Zach Kerr
So, what is the path?
I think it starts with re-signing some players...
DJ Humphries
Justin Murray
Rodney Gunter
Jonathan Bullard
From there we can add some outside FAs...
DJ Reader would be great, but I don't think Houston lets him go.
Same with Chris Jones from KC.
I think three names I would look at would Jarran Reed, Derek Wolfe, and A'Shawn Robinson. None are huge names, but all are proven dudes. Wolfe and Robinson have experience at the NFL level in a 3-4 and Reed did in college.
The offensive line is tougher because I don't know how many of the FAs actually get to free agency.
Conner McGovern and JC Tretter make sense if they are not franchised and we are not sold on Cole and Gaillard.
Daryl Williams and Mike Remmers are options at RT, especially if we want to keep our options open to taking a T high in the draft.