User import from CSV files has very little tolerance for non-alpha and accented characters. Dashes, periods, apostrophes, etc, all have to be search-replaced. For accented characters, a good tool for this (and many other tasks) is the free Excel plugin ASAP Utilities. Once installed, used Text > Remove accented characters. Other odd characters may get past these efforts, so if an import fails, check the status and the number of successful records created. Usually there will be an offending character right around that same line number in the CSV.
For Alumni Imports, use the saved template. The CSV should have these column headings:
Instagram Feed API Access. The site was initially set up using credentials generated with a Primacy-owned account. Syed documents here the process for registering an IG Client ID and cofngiuring the feed in Drupal. Thanks Syed!