For the second point, CC3+ scales to paper on print. The map itself should be scaled according to the actual real world size, not the print size, so if you wish to cover an are 500 by 500 miles, set the map dimensions to 500 by 500.

In the print dialog, you can then specify desired print scale when you print, or if you export to an image, set the desired pixel size as needed by your print.

When you save a custom pal, it saves a file called fcw32.pal in your CC3+ data directory. If this file is present, ALL maps that doesn't have an attached palette will use this instead of the default palette. So the solution is to delete or rename this file, and CC3+ will revert to using the default again.

Check that you haven't disabled Hotspot under Tools -> Options -> Links and Hotspot are active.

An additional thing to look for when things doesn't seem to go right is the number of selected items during the command. The command line will show the number of entities selected when you do the multipoly, and if you expected to multipoly 2 entities, but the selection tells you 3 selected, then that is a good indication that you have an extra entity in there somewhere, possibly a doubled-up one like here.

Is that red polygon in the middle a separate polygon you can manipulate? Could it have been there from before you assembled the multipoly, perhaps as a copy of the blue entity?

Multipolies take on the properties of the current settings when created, not the properties of it's member, so that the multipoly itself became an outline could just be that fill style was set to hollow when you issued the command.

But, if that central red section is part of the multipoly itself, it is something I haven't quite seen before. If that is the case, can you post the .fcw file so we can take a look at it?