Well, I can only answer the Memory/RAM one, sorry... I only usually run the server without the GUI.
Memory use: The server looks like it's been given 1024MB of RAM to use, hence the statement that it's using 750MB and has 36% free. You can increase the RAM in the startup.bat or startup.sh script that you use.
If you want to remove the Minecraft Server GUI and just keep the console open instead, add 'nogui' without the quotations to the end of your startup script.
Sorry for the fairly small amount of help. I think everyone else is asleep.