1 in. Slip
No you will need a brass garden hose thread adapter. You can search for it on the website.
For a sprinkler system schedule 40 is typically used. You can use 3/4 inch or 1/2 inch but you will need to design the number and type of heads based on the pressure, which is affected by the diameter of the pipe. Some water meters and valves have one inch connections. For those you would use a small section of 1" pipe and a reducing coupler.
no, incorrect threads
This question should be posed to the pipe manufacturer. However, if the 1" furniture grade pipe is the same outside diameter as standard schedule 40 1" PVC pipe, then yes. Most likely, yes, 1" PVC pipe is usually 1" PVC pipe. Dura fittings are not furniture grade.
2.37 in. or 2 6/16 in. All the actual dimensions are included in the homedepot.com website data.
3/4" pipe threads
To make a female tap hole for our ¾” M.A, you need to use a ¾”-14 pipe tap.