In reference to your query, please note that Section 45(5A) has been introduced in the Income tax Act w.e.f. AY 2018-19, which provides for the computation of capital gains in case of JDA and states that the same would be taxable in the year in which CC is received.
However please note that this benefit would be available only in case the landowner is an individual/HUF.
In so far as GST applicability is concerned, in relation to agreements executed on or after 1st April 2019, in case of provision of development rights given by the landowner to the developer, the same is taxable under RCM on unsold units portion in the hands of the developer in case of residential projects.
While for the construction service being provided by the developer to the landowner, GST is leviable @ 5%/1% on the basis of 1st independent sale made by the developer. In this case however, a benefit has been provided to the landowner that if he sells his units to another buyer before receipt of CC, then landowner would be eligible to avail ITC of the GST so paid by him to the developer subject to the condition that the value at which the flat is bring sold by the landowner to another buyer is than the value at which tax was collected from him by the landowner.
In your case, GST would arise should you opt for option 1.
NO GST on your part would arise if you go for revenue sharing model.
Please advise in case of any further clarification.
Thanks & Regards,
CA Aditya Dhanuka.