Current codebase optionally supports couchdb only for documents as an alternative to storing those files on server filesystem. I referenced Couchdb in context of storing loosely formatted data streams emitted by various devices. Couchdb, a noSQL database, is not an general option for this SQL based project.
Good news is @sunsetsystems already took care of importing LOINC compendiums in proc orders. I have not looked at recent code but you cheat by setting up a hard coded vendor and import a file to establish the tree structure of 1000s of testing items. Several community members should be able to help in that area.
mysql requires SQL statements provide dates in YYYY-MM-DD format. There are standard php or javascript functions that map some of the formats based on user preferences for display purposes. Standard Date classes in php or Javascript would handle any other conversions.