I think they will be important. When has Oda ever introduced minor crew members first, or even given them speaking roles? Most likely they are two of five or six officers in Big Mom's army, maybe the strongest, maybe not, but certainly among the highest ranking Big Mom pirates. Oda has never given average crew members high bounties or devil fruit powers. We know Pekom's has a very high bounty and we know he is a fruit user. From Buggy the Clown arc forward fruit users and high bounties are reserved for Captain's and officers.
Bounty does not equate to power levels, Robin had an 80 million Beri bounty as a child, but it does equate to how wanted a character is. The higher the bounty the higher the crime is in the eyes of the government. An average crew member would never receive a 300 million bounty, a bounty that high makes Pekoms at least a Level 5 prisoner in Impel Down, if caught. A bounty that high is reserved for high crimes, such as being an officer in the employ of a yonkou. Why would the government give him such a high bounty if he was simply a crew member?