I have family members who work in the US Marshals that I will be seeing soon for Thanksgiving.

While I can certainly submit tips to the FBI, such process is rather impersonal and is just more cumbersome than talking to a relative in federal law enforcement, who agency's mission is the apprehension of federal fugitives.

Given the January 6 rioters have all been federally charged and have active arrest warrants for felonies / misdemeanors:

Would the US Marshals have legal jurisdiction to arrest and bring in front of a judge such folks?

Is legal jurisdiction to arrest dependent on the taskforce / unit assignment?