Ex RAN River/Bay class frigates could be a good fit for the coast guard. There is a 1/350 USS Tacoma as well as 1/700 Rivers available.
My dream modern RAN consists of several identical task forces (five with ships for eight to support the maintenance and sustainment cycle), each consisting of a DDH, DDG and DD, with sufficient available OCV/Corvettes to be attached for support. This would consist of Hyuga / Izumo type DDH, a Hobart or Burke type DDG and a modified Zumwalt DD (perhaps even CG version). There would also be an amphibious group sustaining a deployable squadron of one LHD/LHA. an LPD and an LSD, plus a seabase, several dual role AKE/AORs, and heavy landing ships. One SSN and one SSG flotilla as well.