Can I stack headers in a load bearing wall?
Yes, you can stack headers like that when you're not attempting to combine them to meet loading requirements. Here we assume that the new LVL is adequate by itself.

Crush probably isn't a concern unless there are more than two stories above the beam, and strapping probably isn't necessary if there are other means of laterally fixing the components (end nailing or toenailing). 

All that said, there may be factors I can't see from my house. What you've shown us looks fine. 

By the way, the new king studs aren't necessary. Eliminate them if you'd like to maximize rough opening width under the new beam.