Hi Theresa,
Just came across your post and I will try my best to answer it.
Disclosure: I am not an mortgage broker nor am I an investor but I am a licensed real estate agent in MA.
question #1: You can pay for an appraisal but you can also work with a licensed real estate agent in your area to have them do a CMA (Comparable Market Analysis). From the posts that I've read, it seems that most investors work with an agent to determine the value and to sell the property.
question #2: Can't say that I've seen this on listings and it's not something that I would personally use. If the property is priced accordingly for your market then it should get offers that are around the asking price. No need to oversell.
question #3: FHA requires 1 appraisal but it is a tougher appraisal process vs someone using a conventional loan. FHA approved appraiser must determine value for property and also do a health/safety inspection. A home inspection is not required for FHA but most agents/lenders will still suggest it to buyers. If the property has had an FHA appraisal, you can use that value. But, know that just like any other appraisal, it's someone's best estimate of the value and may not always be accurate, especially if the appraisal was done a few months ago. In some parts of the country the market is changing quickly. This is where an agent with knowledge of your area can be very useful.
I hope this helps!