Unfortunately this is for adapting lenses to Olympus' modern digital Micro 4/3 cameras. It won't work with the Pen FT or similar half-frame film cameras, and you most likely won't find anyone making adapters for these. 

Your Nikon lenses will mount to the XT3. Adjust aperture with the adapter. Manually focus lens. 

yes, the filter size is 55mm and your Nikon D3400 AFP-DX 18-55mm lens size is 55mm, so the filte can fit your camere 

FD-EOS fit for Canon FD mount lens and canon EF mount camera body. canon 60d is EF mount, so the adapter ring can work with your camera, but you need to check your lens mount. could you pls let us know your lens specific model? service(AT)kentfaith(DO NOT)com, Please note: It is not same between Canon FD mount and EF mount, this adapter ring is only for Canon FD mount lens, please contact us if you want to purchase for Canon EF mount lens. 

If your tamron 28-75 lens is 67mm, the two filters both work for your lens. Please verify your camera's lens thread size before purchase (usually marked somewhere on the lens barrel or printed underneath the lens cap).The number is always preceded by a "ø" (diameter) symbol the two lens difference is the stops.