Tinning Flux has a small amount of powdered solder in the paste that makes soldering easier. You can use Tinning Flux on Low-Lead Brass if you are a novice user of solder products, or for large diameter piping systems to help make the process easier.    
The best flux is Oatey H2O®95 and Oatey Silver Solders.
The #95 paste flux contains a silver solder tinning powder which helps fill in the joint when heat is applied, #5 does not.
Yes. All Oatey fluxes are lead free and are NSF listed to Standard #61.
Flux is formulated to clear the pipe and fitting of any surface oxidation.
Yes. Once the male threads are wrapped properly you can apply a coating of pipe joint compound over the thread sealant tape before assembling the joint. Remember that you only apply pipe joint compound to the male threads.  
At this time; Oatey Great White is the only Oatey Pipe Joint Compound that is FBC approved. 
This is because of UL listing requirements.
Under normal pressures the pipe joint compounds does not need a curing time. If the pressure in the lines is 125psi or higher, the recommended cure time is 4 hours before initiating pressure. Call Oatey Customer Service when in doubt.
Oatey does not have any products that will work in this application.