yes it can
This doesn't dry it stays tacky, its pretty easy to clean up though if it does get on anything.
There are better alternatives. Use a sealer based pipe dope like Leak Lock, Block, etc.
Yes, I have used it to seal fittings used on LP gas on the pressured side (before the regulators) and the low pressure (after the regulators).
yes, that's why i bought it
This is an excellent product. This would be a really good thread sealant to use for your application. It contains Teflon, which is a lubricant that helps you tighten and loosen the fittings. Also, this type of sealant is known as a "soft set" sealant, that won't dry and harden. Soft set sealants are easy to dissemble. Also,it is compatible with almost any pipe material and a wide variety of fluids and gases. I would absolutely recommend this product.
The shelf life is 2 years minimum, as noted from the manufacturer. Generally you use smaller cans for smaller pipe and larger cans for larger pipes.
Yes. No problems. I use it on propane and natural gas. Also water.