The new wolf variants are spawning as one individual wolf, not multiples no matter how many they are supposed to spawn as. I am playing on Bedrock on survival mode on a Realm I own, so I am talking about natural spawn rates in survival.

For example, I've been in a Savannah Plateau to try to get some spotted wolves and only one wolf has spawned in the last two and a half hours. I've tried flying away and returning, just sitting AFK, killing all the passive mobs that spawn, running around, and nothing has triggered another wolf to spawn. I confirmed I am for sure in a savannah plateau biome. I have collected all the other variants except the snowy variant as I have to travel a bit of a distance to get to the right biome.

• The Pale Wolf spawned in groups of two to four wolves.
• The black wolf often spawned two at a time, it's the only new variant that spawned more than one wolf in an area. They spawned pretty prolifically, too.
• I was able to get 6 black, 4 chestnut, 4 pale, and 4 woods wolves in 2 hours of waiting in an area of my seed that has the biomes for the four variants all right next to each other. This was with the chestnut and woods wolves spawning one at a time, the black spawning two at a time, and the pales four at a time.
• The striped and ashen wolves spawned one at a time and I was able to get two of each in an hour.
• The Rusty wolves spawn one at a time and took an hour to get two.

As I mentioned, I haven't tried for the snowy wolf yet. I don't know if the seed makes a difference, I am on seed 1229111223.