Perhaps due to the materials consumed, Beginning and Lily were now four and three levels higher than his previously strongest undead, respectively.
Clearly, both the quality and quantity of materials used during their evolution had made a difference.
But even beyond that, seeing their current strength reassured Michael. With this kind of progression, he was confident: evolving his undead would eventually take them to Rank 3 without question.
If he had once been unsure about Lucky reaching that threshold, he certainly had no doubts about Beginning or Lily now.
Of course, with the material Michael had prepared for Lucky—the Poison Wyvern Blood Essence, taken from a beast just shy of Rank 3—even Lucky wouldn't be lacking after evolving. From Level 25 to Three-Star Extraordinary rank, he should be more than strong enough.