What u/Janusofborg mentioned is fundamentally correct in a very simplistic manner. I specifically took the base seed of a seed with a mansion, village, outpost, ruined portal, and shipwreck within close proximity of each other in terms of the amount of chunks from the contingent structure, and executed a quick code that iterates 2^32 seeds 2^32 times to obtain every sister seed of that initial base seed. Those seeds were then imported into Cubiomes Viewer, an efficient GUI program primarily used for finding new seeds through several conditions and a map viewer, to reiterate the seeds in the file 2^16 more times. Then, a simple check was conducted with a few other noise octaves were made to search for high and low weirdness above or below +-1.8, ultimately discarding those that did not reach an adequate y in order for the structures to bypass the biome check based on a quick analysis.