Need Advice On Best Way to Design Index to Filter Photographs by Person(s)

The way a pro would do this is with a database model, probably using Access instead of Excel. You would need more than a simple filter to retrieve data.

Another option would be a photo portfolio management tool. I haven't used one but I think Adobe has this kind of thing, maybe built into PhotoShop.

Here is a hybrid way to build a database model in Excel. This just gives you the concept. I would have to have more information to do a complete design.

Sheet People: List of all people that appear in any photos
A: Unique serial number
B: Person's name

Sheet PhotoPeople: Map people to photos
A: A person's serial number
B: serial number of a photo where that person appears
C: VLOOKUP formula to get the person's name from People

Then you can filter on C to get a list of photos. You can add more columns with VLOOKUP if you need other data for the photo besides the serial number.

Sheet Events: List of all events
A: Unique serial number
B: Event name

Sheet PhotoEvents: Map events to photos
A: An event's serial number
B: serial number of a photo for that event
C: VLOOKUP formula to get the event name from Events

Then you can filter on C to get a list of photos. You can add more columns with VLOOKUP if you need other data for the photo besides the serial number.

....and so on for Location, etc. (You said "etc." but I don't know what the etc. things are)

Sheet Photos: List of all photos
A: Unique serial number
B: Date
C: Description specific to the photo
D: Photo file name, archive number, or whatever you use in your physical photo management system

The serial numbers in all cases are arbitrary identifiers that don't have intelligence about the data, just a pointer.