The Airhook will support all phones and tablets up to 9.5 inches tall (when horizontally) that are 1.5 pounds or less. Using the support bungee and toggle you can adjust to your preferred device. The current max device width is just under one inch (20mm). The cases that we found to be too large were the childproof, thick silicone cases, larger Otterbox cases, or those with additional carrying compartments on their backside. In those scenarios, the case may have to be removed once in-flight for best use.
All airline cups, plus cans and bottles [up to 16 ounces] using built-in can support that can be lowered from The Airhook's base.
No. Not only is it not safe, it is non-compliant with Stowage Federal Regulations (which is why the tray table must be closed too).
Yes, according to the rules in the current Code of Federal Regulations. Please note, it is very important [and the law] to always comply with airline crew member instructions.