I couldn't be certain about this because I haven't done the research. However, in my opinion I think they are all created names.
She prefix 'She' or sometimes "
Che" is quite popular at the moment.
Shemara - is probably just
Mara with the She prefix.
Shemika - just a different form of
Tamika, I think.
Shemahlia - again, was probably just Mahlia /
Malia with the "she" added.
Sherece - I actually this this is probably just an alternative spelling of
Cherise.