Cost for Eviction suit.

We are having an open plot of 1500 sq.ft in a prime location of Mumbai. This plot has been given out to three different Garage workers with a non-registered Conducting Agreement for monthly compensation for a period of 11 months in June 2007. These workers after getting into possession of the premises filed a false suit of ownership in the City Civil Court and pleaded for non-eviction from the suit premises. The above suit was heard and tried and finally dismissed in 2012 for which 2 of the plaintiffs filed a fresh suit in small cause court within 10 days of the Dismissal. The court had offered them ad interim relief which is still valid. The remaining 1 re-opened the case in the City Civil Court itself ( I can't understand how) and finally, the suit is dismissed in March 2019. This person is now applying for appeal in the High Court which we want to avoid to happen as their tactic is to keep buying time in the case and keep enjoying the business on the suit premise and not paying a penny since the filing of the suit in 2008. The lawyer had suggested for the eviction suit to be filed by us if we want to punish them for their deeds and we are setting ourselves to comply with. But I want to know the 1. Method of calculation of Stamp Duty. 2. The claim of monthly rent we can claim through the suit as there is no rent agreement in our case. 3. What can be done legally with the persons who are enjoying ad interim relief in our property? 4. How much appx time would it take for a judgement of the evition suit. 5. What are the benefits after having an order of eviction? And 6. Other possible avenues we can rely upon? I would be highly obliged and thankful for the genuine and helpful reply. Thanks & Regards.