Going the JH route might allow for the best overall continuity, all things considered.
Except, finding that “solid OC” might be the hardest pickle to preserve of the bunch.
Can’t hire away someone else’s OC. Lateral moves not allowed, plus teams will protect that asset.
If an OC is available and on the street, then there’s a reason, and that’s likely someone to steer clear of. The next best two options would be hiring a positional coach as your OC (like a Ben MacAdoo). Could be a lot of risk in that unless they were an OC in a previous stint with an NFL team.
The other option is to go the college route (either a HC or a hot OC), but that’s no guarantee what they’ve done in NCAA translates to NFL.
If they can find the right OC, this option makes the most sense to me.