Dear Dempsey,
you have probably found another way round. But I would still like to answer the question (even if it is too late) for future applications.
If you know the occupation from an ECP run, you can manually set the number of occupations (closed-shell) or (UHF). Delete all ECP stuff and add the X2C/DKH/BSS kexywords (X2C is recommended nowadays). You do not need soghf for DKH runs, you can use 1c and 2c DKH. The first option only needs $rdkh and the order. X2C needs $rx2c.
After setting the occupation, you can use the hcore option, as this starts a calculation from a core Hamiltonian guess (1e integrals only). This does not need Hückel vectors or eht data. In the upcomming V7.8, you can use hcore -a or hcore -atoms to use a superposition of atomic densities as initial guess. As there are no Hückel vectors, you need to set the atomdens keywords for the orbital basis set guess. Then, the basis set is used to construct the atomic density.
Best,
Yannick