Point 1 - If you're doing something as simple as that, you COULD just create a simple Query (in the Console) with a simple filter of the following quasi-code:
Computer.Device Type == Blah
OR Computer.Device Type == BlahBlahBlah
... run that query and either "view as a report" (for a one-off) or create a report based on the LDMS query (New report - use LDMS query for the report).
Inside the reporting tool (for filters), you've got the "IN" Operator for "must be in one of these..." options.
EQUALS is one of those "Must be X and ONLY X". Whereas if you want muliple options ... that's what you use the "IN" operator for.
Sounds like you may not be familiar with SQL potentially - in which case I'd strongly advise your boss to get you signed off on getting some SQL training (basic stuff, you don't need to become a DB admin). Understanding how SQL queries work & such will help you greatly with reporting ... as it's built on SQL .
Hope that helps.