I do not know where the Imbers came from originally. I will try and get that information from my uncle. I saw Lucille and Thelma a couple of years ago at Ernie and Jeanette Dicker's 60th anniversary. Sonny, their brother (who had been married to Dotty) had passed a while ago. I never had the opportunity to meet Harry. My older brother is actually named after him.
I do recall mention of the Presant family as a relation, and I am sure I have met some as well. I also recall when I was very young going to the family circle, I believe that was what they called it. I think, but may be wrong, that it was hosted on a Presant property. It was like a huge extended family picnic. It must have been on a sort of ranch because they had a stable with horses and a large pond or small lake. Did you ever attend one of these?
From just researching, I found that Thelma Imber Seifer, who was Harry and Rose's eldest child passed in 2009.