Yeah, let's be clear, we're not taking an OL with the 16th pick. Period. Either we trade back and consider it a possibility, either we take some later believing we can groom them even without Castillo.
If we're picking an OL in the second, Elflein is my absolute favourite. He's refined, versatile and has it between the ears. Day 1 starter, whatever happens with the other OLinemen.
Trading back is still an option because you can get a top12 player while gaining a 3rd or 4th (picks that Ozzie usually nails), and this class is one of the best in recent memory, so there's really a ton of plausible strategies.