m, I looked at the bowl and thought it could be Venetian glass, maybe Barovier. I'm afraid I know less than you do about it. The iridato finish looks like something that would be done in Murano. I'm not sure exactly when iridato became popular. I know several companies were doing it in the 1930s. I'm trying to remember any earlier things that had the finish, but I'm not coming up with anything.
There were some workers from VA Barovier that formed another company together in the early 1930s. The depression hit VA Barovier hard, so they had to let many workers go. Antonio Seguso and sons, including Archimede, left VA Barovier in 1932 to form their own company. The next year master Napoleone Barovier joined with them, along with Luigi Ferro, to form Barovier-Seguso-Ferro. BSF did a good bit of quirky work and experimented much with iridato. BSF reorganized to Seguso VdA in 1937. Strange to think that the Seguso companies also evolved from VA Barovier. It was like the company that gave rise to the subsequent lines of great Murano glass, but the company itself was to weak to survive the times.
Napoleone Barovier was very important to VA Barovier and had been a master glassblower with Artisti Barovier. He is a very important person in glass history, though many have never heard of him. I consider him the father of massello sculptures. He is the one that first started executing those solid glass animals VA Barovier is known for. And not surprisingly he took Archimede Seguso under his wing. No wonder Archimede loved the animals so much. He learned from the master.
Well, I could talk on, but it just gets confusing to weave things together. It makes one realize that things are never black and white on the island of Murano. I really just wanted to mention Napoleone Barovier as a possibility if you're researching, since he was a master glass blower for Artisti and VA Barovier. Perhaps the bowl design is from the BSF branch of the dying VA Barovier.