@Harsh PoshtiThis will be dependent on the area and I would recommend you perform a market study to determine which project would yield better results and if either is even viable.

Studying for and receiving the CCIM designation will be a solid plus.  

Get a no-cost estimate for an engineering-based cost segregation study on every investment property you own over $250K in purchase price.

Please study engineering and you’ll have more of a grasp of why measuring amperes (electricity) or volume (water or natural gas) lends itself to reasonable precision.  

For the first part of your question even if you were working with a realtor, I don't personally know many that have a true pulse on rehab costs and I wouldn't make any investment decisions based on their rehab cost projections.My suggestion would be to study how to evaluate the Big 6 rehab costs: roof, siding, windows, HVAC, electrical, and plumbing. 

If you study the economics of this industry, you'll see that it's very much like a sports team.  1% makes most of the money, then a small 2nd tier of agents do some transactions and a majority of the rest do nothing. 

Financing is definitely an area that I will need more study.

Night Before the Exam dot com is a good state study test if they have it for your state.To be clear though, the majority of what you learn in the class is not used by residential real estate agents in practice.

Print them off, study them, highlight them, make notes, read some blog posts, and understand the subject.The second document he links includes precise definitions and a guide for landlords to use for screening support animals.

Due Diligence and Feasibility Studies - What studies or tests are essential before purchasing raw land?