you say "As I understand it, it is illegal to cohabitate.." and at the same time you "don't want to come to this beautiful place and be overtly offensive to the culture"..
so since you know this is illegal, you understand it IS "offensive to the culture"... you contradict yourself..
On the other hand, your GF can NOT just come and live here. She needs a permission to live here, i.e. Residence permit. To get a Residence Permit, she needs a sponsor. Sponsor can be either the Company that she works for, or yourself (only if you guys are married)..

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"What lies behind us and what lies before us are small compared to what lies within us."
Oliver Wendell Holmes