Hi Carol,
1 - There is no configuration option to add a legend to a Map Tour at this time, but you can add some text to your subtitle to denote what the colors mean. See this example. The text fields in the Map Tour support HTML tags, so to change the styling of some text use a <span> tag as shown below with a hex color value or name.
My map tour title contains <span style="color:dodgerblue"><b>some bold, blue text</b></span>.
2 - You can add a label to each tour point by opening the web map that was created when you made your map tour and configuring labels on the tour point layer. You can find the web map in your My Content (it should have the same name as your Map Tour app) or use My Stories on the Story Maps website to find your Map Tour and click Edit Map to open it (see this blog post for more info about editing a Map Tour web map).
Regarding #2, To avoid cluttering the map, I'd recommend using labels only with a plain basemap like the grey or dark canvas. You could also consider only labeling certain key tour points instead of all of them. To do this you could add a copy of your tour point layer that you filter to only show the points you need to label.
Owen
Owen Evans
Lead Product Engineer | StoryMaps