Note that even if you do not know the name of the fill, you can still use CHANGEFS, if you just let the fill name be blank when asked and just hit enter, you will get the fill style dialog where you can pick your fill. (But admittedly, picking through MPEDIT is probably easier as it is a single dropdown, not a dialog with 4 pages)

If you know the name of the fill to change to, the quickest is to use the CHANGEFS command. Type in the command (followed by enter), pick the poly when CC3+ asks for selection, hit D for Do it, and when it asks for the new fill, type in solid white 20 and hit enter. Changing it via the command line do require that you spell the new fill 100% correct though.

Of course, you can also use the more common GUI dialog through :CC2MCHANGE:. If you wish the correct fill style to be pre-filled in this dialog, first use the KEEP (:CC2KEEP:) command on another entity that has the correct fill, and when you then use change properties on the entity you want to change, the fill style you extracted from the other entity is already pre-filled, all you have to do is to check the check box in front to apply it.

If you look at the fills for your polys, you'll notice that all of them (except "F") are filled with "Solid white 20". This is a partially transparent fill, that lets the background shine through.

"F" on the other hand is filled with a plain solid fill, set to white. This isn't transparent at all, and leads to the white appearance. This doesn't have anything to do with the effects at all. Change the fill to solid white 20, and you should see it appear as the rest of them.

On an unrelated note, I also noticed that while you do have a separate sheet for each of the polys, poly "F" is on the contour 4 sheet, NOT the sheet dedicated to it.

I am guessing that when you talk about your house, you're talking about that floorplan of yours, right, and not a city-scale house symbol?

The issue with rotating a floorplan is the way CC3+ shows the outlines. When you rotate vector entities (like your floor and walls), only the outline of the entities are shown for performance reasons. But the downside is that when you have two entites on top of each other, their outlines cancel each other out. And with floorplans, you almost always have that case, because you have the floor entity and the walls entity which are in the exact same positions.

There is no other tool that can be used, but one workaround is to use the :CC2LINE: tool (or :CC2BOX: or similar) to draw a simple guide line somewhere close to the feature you want to align, and when you rotate your floorplan, make sure to include this line when you rotate. You should find that this single line will be nice and visible in the rotation preview. You can then delete the line when you are done.

I am not sure how images would work. The lines for the original lines are just plain simple lines. The easiest way to deal with them is to open up the symbol catalog for editing (@Symbols\Cosmographer\basesym.FSC), the from symbol manager, clone the symbols, and finally, go in and edit the two clones, using change properties on the lines to change their width. You can then save the symbol catalog with both your new modified copies and the original in them, and you should be able to easily pick from the starmap options which of the two to use.

(I normally don't recommend overwriting the original symbol catalog, but for this case, it may be the simplest, providing you do clone the symbols and don't change the originals. But if you prefer to be safe, either save your modifications under a new name, or make a backup of the original first.)