[Tool] Using G2map to add wild encounters where there are none and other questions

I want to try to add Wild Pokemon to the Safari Zone map after making it possible to exit the place. What do I need to do in G2 to allow wild Pokemon to be available? trying to use the table doesn't work because it is greyed out.

Under a similar vein, how do you make a 1-time only scripted Pokemon encounter? Similar to most stationary Legendary Pokemon.

Also what are the index numbers for the various overworld sprites in this program? speficially I want to use the ones for Bird pokemon and the one Mewtwo/Mew use.