How can we improve the quality of the stream for the sharpest and best results and the best speed without lag?
That will depend on the video cables that you are using, if you connect the Slingbox to the receiver using the HD connect, you will experience the best quality. The streaming will be much better if you have a very fast Internet connection
Is there any other software to play the stream besides the slingplayer on the mac?
Is it possible to broadcast the slingbox to more slingplayers?(or other software)
The Slingbox was made to have one connection at a time regarding the EULA End User License Agreement
Can we improve the system so it wont lag when we control the input device with our slingbox?
Unfortunately no, the connections that you have right now are the best options
Do you have any protocols for the slingbox (or the slingbox software) for controlling the slingbox so we can write our own software for that?
Not right now
I hope this works