Do lawyers have to pay gst?

legal firm is RCM.

1. No
2. There is separate provision
3. Yes in this case the lawyer is liable get himself registered.

As per Notification 13/2017 CT (R) legal services by lawyer is under RCM & As per Notification 5/2017 CT , the person supplying taxable services & goods ,the total tax on which is liable to be paid by Recepient on RCM , the supplier is not required to Obtain Registration.
But as you are also supplying rental services (Not cover under 9(3)) , hence your Aggregate Turnover exceeds the threshold limit as prescribe in Section 22 , you are. liable Obtain Registration & you are also liable charge GST on FC (only on Rental Services)