...and I can't find new ones because peer discovery is done through UDP and tor only runs through TCP. Is this an accurate understanding?
Yes.
As per the issue thread you linked to, you could attempt to add peers (using --reserved-peers) from the hard-coded bootnodes list in the ETC (go-ethereum, not Parity) codebase, located in bootnodes.go.
The list, as of late January 2017, is as follows:
enode://08c7ee6a4f861ff0664a49532bcc86de1363acd608999d1b76609bb9bc278649906f069057630fd9493924a368b5d1dc9b8f8bf13ac26df72512f6d1fabd8c95@45.32.7.81:30303
enode://e809c4a2fec7daed400e5e28564e23693b23b2cc5a019b612505631bbe7b9ccf709c1796d2a3d29ef2b045f210caf51e3c4f5b6d3587d43ad5d6397526fa6179@174.112.32.157:30303
enode://687be94c3a7beaa3d2fde82fa5046cdeb3e8198354e05b29d6e0d4e276713e3707ac10f784a7904938b06b46c764875c241b0337dd853385a4d8bfcbf8190647@95.183.51.229:30303
enode://6e538e7c1280f0a31ff08b382db5302480f775480b8e68f8febca0ceff81e4b19153c6f8bf60313b93bef2cc34d34e1df41317de0ce613a201d1660a788a03e2@52.206.67.235:30303
enode://ca5ae4eca09ba6787e29cf6d86f7634d07aae6b9e6317a59aff675851c0bf445068173208cf8ef7f5cd783d8e29b85b2fa3fa358124cf0546823149724f9bde1@138.68.1.16:30303
enode://217ebe27e89bf4fec8ce06509323ff095b1014378deb75ab2e5f6759a4e8750a3bd8254b8c6833136e4d5e58230d65ee8ab34a5db5abf0640408c4288af3c8a7@188.138.1.237:30303
enode://fa20444ef991596ce99b81652ac4e61de1eddc4ff21d3cd42762abd7ed47e7cf044d3c9ccddaf6035d39725e4eb372806787829ccb9a08ec7cb71883cb8c3abd@50.149.116.182:30303
enode://4bd6a4df3612c718333eb5ea7f817923a8cdf1bed89cee70d1710b45a0b6b77b2819846440555e451a9b602ad2efa2d2facd4620650249d8468008946887820a@71.178.232.20:30304
enode://921cf8e4c345fe8db913c53964f9cadc667644e7f20195a0b7d877bd689a5934e146ff2c2259f1bae6817b6585153a007ceb67d260b720fa3e6fc4350df25c7f@51.255.49.170:30303
enode://ffea3b01c000cdd89e1e9229fea3e80e95b646f9b2aa55071fc865e2f19543c9b06045cc2e69453e6b78100a119e66be1b5ad50b36f2ffd27293caa28efdd1b2@128.199.93.177:3030
enode://ee3da491ce6a155eb132708eb0e8d04b0637926ec0ae1b79e63fc97cb9fc3818f49250a0ae0d7f79ed62b66ec677f408c4e01741504dc7a051e274f1e803d454@91.121.65.179:40404
enode://48e063a6cf5f335b1ef2ed98126bf522cf254396f850c7d442fe2edbbc23398787e14cd4de7968a00175a82762de9cbe9e1407d8ccbcaeca5004d65f8398d759@159.203.255.59:30303
enode://42d8f29d1db5f4b2947cd5c3d76c6d0d3697e6b9b3430c3d41e46b4bb77655433aeedc25d4b4ea9d8214b6a43008ba67199374a9b53633301bca0cd20c6928ab@104.155.176.151:30303
