1. You shall have to file a Writ Petition against the Forest Department for its not being able to update records in connection with the agricultural land proposed to be purchased by you as per the sale agreement executed by you, praying for relief with a direction upon the forest department to up date its records according to the records maintained by the Revenue Department,
2. After obtaining the above favourable court order, you may go for registration of the sale deed,
3. If the land has not been converted to 'Vastu', you shall not get your construction plan approved by any of the appropriate authorities. Moreover, the Forest department will raise objection for your such construction,
4. Yes, you shall have to apply for conversion of the land to non agricultural/ Vastu land once you come out of the Forest Department's claim on it.