Legal procedure to buy minor property after sale date execution between first 2 parties.Minor is still 14 years old

Dear Sir. Property description - Flat at greater Noida. First owner purchased it directly from builder and also mentioned his minor daughter name in the property documents. He later sold the property to second owner without seeking court permission and has signed himself in sale deed as natural guardian of minor at sub registrar office and they even got transfer of memorandum from local authority. Now, I have executed agreement to sale at sub-registrar office greater Noida with current owner(second owner).During loan processing, I got to know they didn't seek court permission.Now what is the legal procedure to clear the property title, so that there is not future obligation and can go ahead with sale deed execution.Seconder owner managed to contact the first owner.Lastly, what could be the tentative timeline to clear the title from court, if first owner agrees. If first owner doesn't agree then what legal action can second owner takes? Is it advisable for me to go ahead with deal as I have already paid 10% amount to owner along with stamp duty and registration charges while doing agreement to sale at sub registrar office. Though I am keen to buy the property but with no further legal obligation. Note - Girl is still minor (14years)