No. Forklift LPG tanks have a dip tube to draw off liquid.
Propane engines feed off of propane liquid, and turn them into gasses through an internal engine component. While your traditional propane BBQ grill will feed off of vapors from the propane. Of course if you could change the valves this would be somewhat fixed, though you will be hard pressed to find a propane dealer to fill it. But the correct safety equipment would be in place to fill it (i.e. Fixed Liquid Level gauge). Replacing the valve and keeping the cylinder the upright position would allow you to use it, but by then it is basically going to cost you more than it's worth.
There is only one type of propane that can be used for your BBQ. If you go to any store that sells propane for BBQs you will be able to purchase a tank of propane. However since this is the first time you will be connecting your BBQ to a propane tank you have to make sure that you have the right fittings and hose to connect to the tank.
Propane
Some stores that sell bbq propane grills are: http://www.bbqs.com/, http://www.grillsdirect.com/ and www.thebbqshop.com Those are all great and trustworthy.
That is going to be up to personal preference. Propane tends to have a hotter flame than natural gas. Propane requires tanks, while natural gas can be piped in from your home service. I prefer natural gas, as grilling slow gives me better results than fast.
Propane, LPG, or natural gas (methane)
You can find the instruction manual for your bbq propane grill at the manufacturer's website. You can the company's name on the label on the grill and they probably have an 800-number listed as well, which you can call for immediate help.
Flavor. Or the lack of, compared to charcoal or hardwood.
Lava briquettes
Type your answer here... there are around 91,600 BTUs in a gallon of propane. The standard BBQ sized bottle of propane contains 11 pounds of propane. Propane weighs about 4.2 pounds per gallon, so that 11 pounds of propane is about 2.5 gallons in its liquid state. That means there is 91,600 BTUs/Gal times 2.5 gallons so a BBQ sized tank of propane contains about 2.3 million BTUs. If your BBQ has a 50,000 BTU burner, on high heat, it will last a bit over 4 and half hours of run time.
The majority use liquid propane, and some are hooked into the home's natural gas line.Natural, Propane, Charcoal fuel.
Natural gas or electric=stoves Propane or charcoal=BBQ.
You don't need them for a propane grill. I put them in though because I like the flavor it adds to what I am cooking.