The private key under the hologram should be in the form of a Mini private key. I'm unsure if any of the wallets you mentioned in the OP are able to convert as I haven't tried them. I just recently peeled a 2016 Titan One – 1oz Gold and everything worked smooth when sweeping it with Mycelium. I used the Android version for this. Be very mindful that you haven't capitalized letters that are lower case and that you aren't putting in 0's for O's and vice versa. The text under my hologram was a little bit fuzzy so if similar with yours you could be misinterpreting a letter.

You will be able to find the public address associated with the coin at TitanBTC's redeem page. Enter the digits on the face side of the hologram and hit submit code. The webpage probably doesn't display accurate information about the loaded value (mine doesn't currently) but the full public address will be below and clickable. Let us know how it goes and feel free to message me any pictures you don't feel safe publicly posting.