Taking over a Private Limited Company

I am interested in existing private limited company for purchase/takeover.

The Company I wish to take over is registered in ROC Delhi

I am from Mumbai/Maharashtra

The Company I wish to takeover is 3 years old having 2 Directors, till date the company has filed the 3 years Audit Report, Income Tax - GST Details are yet to be shown.

What are the due deligience to be followed as per the Company Law.

We will be 2 Directors with Active DIN taking over the existing Company having ROC from Delhi.

My Question is how to make Valuation of the Company I wish to Takeover.

My further query is:

1. Can I change the Name of the Company
2. Can the Primary and Ancillary Objectives be Changed.
3. Trasfer - ROC from Delhi to ROC Mumbai 
4. Any Other due digilence to be followed.

Kindly Advise.