Can I charge this gun from my pancake compressor?
The airsource has to be 3000 PSI or above. Most shop compressors operate at 150 PSI .
can we increase the maximum velocity to 1000fps
No you can not, this is a Competition rifle so it is for a specific purpose of 10m shooting. If you are in the the price range of these and wanting a hunting air rifle I would look at a Benjamin Marauder
Will the front sight on this accept standard globe aperture inserts?
Does it come with a sling mount and sling or do i need to buy one or both
You need to buy both.
is it all metal body
Yes, it is.
Does the Edge come with a sling attachment point and if so, does the manufacturer provide a sling with the rifle?
There is no sling included with this rifle
what does one need to fill the tank? Does Pyramyd Air have those items?
If you click the "PCP hookup" tab just to the right of this one, it will allow you to choose various fill methods and then tell you what adapters (if any) you will need.