great photos of all those Yucca, Mags and LL Pines. It's nice to see them growing so far north.
The monster Yuccas sure look like Y. faxoniana. Some references claim fax = carn but theoretically, the flowers are slighly different between the two. Y. carnerosana has two forms, one native to Mexico and one native to the Big Bend area of Texas. The ones from Mexico sure look different from the ones in Texas (at least to me). Faxoniana is hardier too, so to me fax is not an equal to carn.
Here's the video of my protection of my Y. carnerosana 'Mexican form'. Even though it was moisture protected, it died last winter due to the cold.