Welcome to AFF.
Interesting set of questions.
- They are both safe and I would have no concerns with either.
- All these a/c are fine. From the sound of it though you prefer the larger a/c.
- What security concerns are you referring to
Reading between the lines of your post I get that you prefer the larger a/c and therefore would stick with JQ as they are direct and this sorts out all your other concerns. ie no need to transit in BNE and the possibility of an Embraer.
Hope that helps.