Itc in car leasing business

Co. ABC purchases cars and then provides services as following.

To Co. POQ as car leasing services. Co. PQR gives such leased cars to its directors and other senior employees.

To Co. XYZ as cab. Co. XYZ is running a call centre and is under mandate from govt. to provide cab to its employees.

Questions are as follows:

1. Can Co. ABC take ITC of GST and Cess paid ?

2. What would be the applicable tax rate in both cases ?

3. Can co. PQR and XYZ calim ITC of GST and cess charged by Co. ABC.

4. Is it required to have a yellow number plate or will the same make any difference ?