In January 2020, rhodium was about $8,000 per ounce, while gold was about $1,550 per ounce and platinum $1,970. Rhodium is the most expensive of the "precious metals". 80 to 90% of production is used in automotive catalytic converters. About 80% of the metal is mined in South Africa (not South America), with the majority of the rest coming from Russia and Canada.
McGee mentions the secret band group was started when an entire Navy Band was killed at Pearl Harbor. This would be the band from the U.S.S. Arizona (BB-39). The ship's band was passing ammunition under the No. 1 turret when the explosion occurred that killed most of the crew. The black and white picture McGee and Bishop bring up in Vance's office is of the Arizona's band, taken on November 22, 1941.
Although it sounds odd, occupations are part of Naval rank. From the Navy website: "After completion of recruit training and upon arrival at the United States Navy Band, members are advanced to the rank of musician first class (E-6 pay grade)".
Some of the musicians in the secret club are actual real-life members of the United States Navy Band, the woman with the short hair that places an item on the podium can be seen on the band's official website.
Ducky says that batrachotoxin comes from the Golden Dart frog, it is a member of a family of frogs called Poison Dart frogs due to the use tribesmen found for their natural defence. These frogs are not the only animal that produces the toxin, it is also made by several species of beetles and even birds, across Central and South America.