It's tough to predict this year without knowing more about Lucas. I don't think this FO will draft a guard at #16 but they would definitely draft a right tackle with the ability to play guard. If we have long-term doubts about Lucas then I can see them staying at #16 and picking a versatile RT.
Who else would we stay at #16 for? It might be a pretty short list if they feel they can get decent players on day 2 and try to recoup the draft capital spent on Williams and Howell. Not picking again until #81 is a long gap.