15ZX2yUZio9HeSWUeWubxznQyaYcYFBFzB is the address that twipple received a loan to, more specifically via 1114a697d9636307d31afaeb8cc0c55af37cd82ba7acaf80b333dcf67d7fb780. The post requesting the loan seems to be deleted from the thread in question on bitcointalk, however the post was captured by bitcointa.lk here (archive).
15ZX2yUZio9HeSWUeWubxznQyaYcYFBFzB and 1Fo6Uy8JWnV9SnDM5LBnYA8nnCQgbfbyDT both signed d515a082b1df9b515e8f826cae84f41629183f26575bd014ba3d32ecddc9b633. 1Fo6Uy8JWnV9SnDM5LBnYA8nnCQgbfbyDT and 1Fz6xXind3Kovsw4ArW6u7oMXRZTUSBj1G (the address that tacoman71 received his stolen BTC to), as well as 19t4Cp3ftH3XTu6c4HhHTTpRP9TxDJVz87 all signed bfd3ec181aeae8abd8da9e63f6c4772ff8fceb6d4c0f3472cac66b6c77649353. This connects the "old" twipple to tacoman71.
19t4Cp3ftH3XTu6c4HhHTTpRP9TxDJVz87 was posted by Madern, here. This links Madern to "old" twipple and tacoman71
Madern posted that he purchased an account (he was the OP of this particular thread and this post was most likely a mistake), and referenced txid 754c1604f0e0d86bb62e2335d1cfd727f4ea7aae742f7d3b49a51363312e20fc, which was signed by the same address that funded the twipple loan, 1QG9PhaEwiF5nsJHkGuPUpQ3p2UbnEA9cP. This links "old" twipple to Ume, as well as to Madern.
According to this post, lolxxx is the same as Ume.
It is claimed that twipple was purchased from Ume, however I believe this to be untrue for many reasons, one of which is that the loan to twipple was actually a loan to himself, and a second of which is that the person buying twipple is using TOR, or at least did to initially change his PW.
There are a number of other rabbit-holes that involve additional alts and additional scams, however I decided against going down them. One of these rabbit holes apparently involves ddamianfrt7 possibly being an alt of Ume et al., who received a triple payment and refused to return it.