Can't answer about the missing 30-amp fuse, but for #10 & #11, it appears from the photo that nothing is connected to them. If there is no wire attached leading to a circuit, then you have two extra positions you can use at a later time to add circuits.
Looks like the missing 30-amp fuse MIGHT have something to do with reverse polarity protection, but you'll have to check with your manual or someone more informed than me on this one.
1994 Excella 25 Follow the build on Gertie!
1999 Suburban LS 2500 w/7.4L V8
1974 GMC 4108a - Custom Coach Land Cruiser