I found the story about Mr. Ruggles. It is included in the 33 page biography of Strong that precedes the diary in Volume I. (Current entries are from Volume II.) In 1851 Ruggles hatched a plan to build warehouses in Brooklyn and lease them to the government for $60,000 a year. He borrowed heavily to finance the deal. Dissatisfied creditors refused to renew their notes and Ruggles was ruined. Some wealthy friends helped him get out from under but "he continued to be burdened by debt down to the eve of the Civil War."
I still haven't found any hints about how the Strongs and Ruggles fared in the Panic. Maybe they will appear in George's future entries, which I haven't yet thoroughly read.