Just finished this spreadsheet, which shows which bard archetypes are compatible with one another (second sheet, called "Compatible Archetypes").
Next will be figuring out how many you can stack, but figured I'd share it as-is in case someone finds it useful.
Comments/suggestions/corrections are welcome.
The Archives of Nethys shows what gets replaced within each Archetype on their tables. You can use this to easily see, at a glance, what archetypes can be combined.
It is up to date with every Paizo-released book that includes archetypes (only missing books are Bestiary 2-3, GMG, NPC Codex, and Ultimate Equipment).