1. Franklin Armory's DFM magazine (also requires opening the upper, but easy to take out if ...)
2. BB 2.0 (need to open the upper to reload)
3. Register
4. Sell to out of state
5. Move out of state
Since a strip lower doesn't have any of those evil features, I think it's OK to leave them stripped. But you won't be able to turn them into "AW" any more if you don't register them. I think some people will build them into featureless just to be safe, although I don't think it's necessary. We might still be able to buy stripped lowers before some other laws to ban them in the future. If the vendors will sell them is a different topic.
Or you can also get a DFM magazine and stick it into the lower to be safe. That magazine is pretty "fixed".