You are competing against cash buyers, as is close in a week vs you are closing in more than a month, appraisals, inspections and now this tenant issue.

It took lot of money and we went overspending on the property more than the appraisal value.If we sell the home we will end up in loss.

Give me a day or two and I'll get an answer from the local county appraiser here in College Station. 

Will I get dinged on the appraisal enough to make it worth changing the furnace ahead of time?

For example, if a 1,600 sq ft main house is appraised at $100 sq/ft, what could I expect a 600 sq ft ADU of similar build quality to be appraised for?  

Buyer's agent may portray himself as the procuring cause for the buyer, and sue the buyer for the commission.Personally, I would go to the seller, offer to increase the purchase price by $6,000 (assuming the appraisal will bear it) and put the $5,000 commission on the seller.

The appraisal indicates the rents will cover 1.1 of the PITI, and the credit is good, with 20% down, solid savings, and a W2 earner (a beautiful lending profile).

Offer contains Appraisal Gap Coverage2.

The other aspect is identifying what I call "Ugly Inventory" so that you find homes that can still pass an appraisal and not be "Subject to" so that you can do some TLC with repairs/renovations to borrow off of the ARV.

Appraised Value - Is there room for the home to appraise beyond the current listing price?