The picture above was not labeled or dated so we must apply some logic and guesswork to identify the people in it. Some known facts that we feel sure about are: it is a picture of Emma's wedding, not Marie's wedding. We have pictures from Marie's wedding and they clearly show Marie and Uncle Eddie in different wedding attire. The date of this wedding was April 28 1918. The gentleman with the mustache is definitely Albert Mathea at age 54.
The woman on the right must be Julia, age 44, mother of the bride.
The Flower Girl is not Julia, who was almost 8, It is more likely that the Flower Girl is Anna, who would have been 13, The bridesmaids are Marie, who would have been 16 and Ella, who would have been 20. But which one is Ella and which Marie?
The gentleman to the right of Dan is perhaps his Best Man. There seems to be a strong resemblance between them, suggesting that this person could be Dan's brother, although we don't know whether Dan even had a brother. This person might also be Dan's friend Andrew Kolarsky.
The gentleman to the right of Albert is unknown. It could not be Albert, Jr., who was only 11 at the time of the wedding.