Q1: The total number (10) is the number of unique visitors that have interacted with your site over the period. The daily breakdown will give the number of unique visitors for that particular day. So if the same unique visitor visits your site over multiple days they will reflect in each of the relevant days but from a total perspective, they are still seen as one unique visitor. Adobe will always try and answer your question the same way a person answers it (ie. How many unique visitors visited your site on May 1 = 1, How many unique visitors visited your site for the period May 1 - May 14 = 10).
As a side note, its important to understand how Adobe will treat your metrics/dimensions - in some instances, given the breakdown provided, sum up (detail = total) but in most instances the detail is a more granular view of the total (like in your example).
Q2: These metrics will be averages. Time spent per visitor will be the total average time spent by a visitor across multiple visits. Time spent per visit will be the average time spent per visit.