There seems to be confusion on this park. Wolff's Park starts showing up in the newspapers as of about 1906 but reading the articles seems to depict what eventually became Electric Park which was near the Belle Isle Bridge. In 1915, there is a new park mentioned (also Wolff) that was at W. Grand Blvd near the Ambassador Bridge in the area of what is now Riverside Park. There was a marina of sorts and some rides.
The problem is old photos and postcards could be confusing. Just which one was which? The article below entitled "Attract Family Parties" seems to refer to Electric Park as it mentions views of Belle Isle. That wouldn't be the case from W. Grand Blvd. The others from 1915 definitely refer to a different park started by Wolff. He even sued one of the local papers for libel over it. There is also a prospectus around that time to attract investment. I doubt that was to further finance Electric Park. So, for now I will assume these were 2 distinct parks and that Morris Wolff was involved in both.