Are Trump's Interior nominees being delayed over the national monument reviews?

Yes, according to this report from the Daily Caller:

Illinois Sen. Dick Durbin has held up the confirmation for four Trump administration nominees because Interior Secretary Ryan Zinke hasn’t met with Democrats to discuss the fate of some national monuments. “Please let the secretary know that while my colleagues and I await his scheduling decision, my hold on Department of Interior nominees will continue,” Durbin, a Democrat, wrote to the Interior Department’s congressional relations office, reports The Hill. Four Democratic senators, including Durbin, requested a meeting with Zinke in late October to discuss the recommendations. No meeting has taken place, so Durbin is preventing key Interior Department appointees from getting congressional approval. Durbin is the only lawmaker to disclose their hold on the four Interior Department nominees, though other Democrats may also be holding up the process as well. All four nominees got unanimous support from the Senate energy committee.