If you press Ctrl+T you toggle between the crosshair cursor and the arrow cursor. This can be done mid-command based on your needs. Note that it doesn't apply to the first point of each command (don't know why it's like that), but to all subsequent points, so if you're drawing a path, the initial node will always be placed using the crosshair cursor, but you can toggle for all the subsequent ones.

Also note that if you use it in the middle of a drawing tool that has the trace capability (like the landmass tool), the shortcuts conflict, so it then asks you for "entity to trace" but you can just right click at this point to go back to the drawing instead of tracing. To avoid it, you can use the menu option (Tools -> Drawing Aids -> Toggle Crosshairs) instead of the shortcut key.

It depends on how you plan to use them, but I would probably have put them all into one symbol catalog, and then used collections to either group them by type (so you have all the castles of different colors in one group) or by color (so you have all the red tinted symbols in one collections).

Install order doesn't really matter anymore. The only thing to be aware of is that some add-ons require the latest update, so it is usually smart to do CC3+ -> latest update -> everything else -> latest update again (because it will update some of the files you just installed from the add-ons) [and yea, ignoring the message that you already have a later version.]

Assuming your friends don't have CC3+, the standard way would be to just export it as an image from the save as dialog. (See page 47 of thr User manual for details about the procedure). Optionally, you can print it to a pdf file instead, all modern versions of Windows comes with a virtual pdf printer installed you can print to to generate a pdf file.

Saved effects settings are found in @System\Effects. They are regular .fcw files

Drawing tools are found in @System\Drawtools. Each style has it's own folder here, and each draw tool is a .dto file, and if it is a macro tool it will also have a .dtm file and optionally a .fcw (for preview) file.

Effects are stored in the map, so existing maps will have all their effects on a new install.