In short, yes. Most lease agreements in the United States include a provision that forbids the tenant from subleasing the property. But if the Lease Agreement doesn’t mention subleasing, you’ll still need to obtain the landlord’s consent to sublease in writing.
It depends on your circumstances. A month-to-month automatic renewal tenancy offers more flexibility but it’s also easier for either party to terminate the tenancy. With a fixed-term agreement, you can reasonably assume a subtenant will remain for the duration of the term.
The subtenant has the right to see the terms of the original lease, so if requested, there’s no basis for you to deny it. It’s customary to include a copy of the Master Lease Agreement with the signed copy of the Commercial Sublease Agreement.
If a sublandlord is sufficiently insured to cover the subtenant, it’s safe to have an uninsured subtenant. However, it’s always strongly advised that both the sublandlord and subtenant have adequate liability insurance.