Dear @Kevin.Chang,
Regarding (1), this is not possible, at least through the input file (changes to the source code would be required). The valid options for hub_conn are: 1: cantilevered; 2: free-free; 3: only axial and torsion constraints.
Regarding (2), BModes uses mass normalization. See the following forum topic for more information: From BModes output to FAST (Blade file).
Best regards,