Could someone point us to information on how to receive / send Mastercoins at this point in time?
We would like to obtain MSC but with ambigous info on what kind of Bitcoin addresses can even receive them, cannot risk losing the precious BTC for using a wrong type of BTC wallet.
- can Mastercoins be received to an Electrum address with its private key known to the owner?
Yes. As long as you have access to the private key it should work.
- does Mastercoin receiving address need to be brand new ie. never seen in the network?
It doesn't need to be but it would be good practice.
You can use the original Mastercoin advisor by J.R. to send coins. If you are on OS X or Linux you can try my wallet software. And soon you will be able to use Zathras's wallet on Windows.