Greetings,
We were contacted by a close family member, who provided the following corrections:
The photo [of] Ernst Holm... is correct. Additionally, his full name was Ernst Cornelius Holm.
The photo ... said to depict Carl Axel Holm... is not true. It depicts Johan Albert Holm.
The photo ... said to depict Johan Albert Holm... is not true. It depicts Carl Axel Holm.
The three portraits are taken from a photo showing the Holm Brothers' orchestra, which was formed in 1931. The photo was probably taken in the first half of the 1930s.
Let me know if you need any help swapping the photos for Carl and Johan.