I see you have a '71 like I do so let me warn you of something. The BAT terminal is unfused and the IGN terminal is heated by the ignition switch. Over time the contacts in ignition switches get worn to the point of no longer making contact so I highly recommend you replace your ignition switch based on years-of-use alone. New ignition switches are about $15 and are fairly easy to replace; maybe an hour's worth of work.
You can power a dozen things from one terminal as long as the combined load doesn't exceed the terminal's rating. In your case the things you are powering are small so feel free to connect several to one terminal.