Do I need to request a search on all nicknames, maiden names and other aliases?

That is entirely up to you and your budget. There is no standard policy for record keeping across US counties and states. Therefore, you cannot assume that the counties will have anything other then the name the individual was arrested under on file. For example, if you are searching for criminal history under Richard Jones and find no records, but Richard also goes by Dick Jones, it is prudent to check for criminal history under the name of Dick Jones as well. Additionally, if part of your search package is Education Verification, a great deal of the time this will be found under the maiden name.