The length of time it takes to sell depends upon many factors; the current market, the number of similar units available, the location, the price......
FSBO seems like it'd be easy, but Realtors are professionals who have the skills,expertise and relationships to properly value your home and to market it widely. They also give invaluable advise on getting your home ready to sell. There's also the issue of scheduling appointments and being there to show prospective buyers your home. (Among many other things.) The percentage you pay to the listing agent is well worth it. Homes that are listed through Realtors tend to sell quicker and for more money. That said, selling FSBO can be alot to take on, especially depending upon your particular market. Make sure to do your due dilligence before listing your home. The first thing you should probably do is find a good real estate attorney who can guide you in the many steps of the process.
Your agent and/or attorney.
There's really no need to offer them anything but your sincere thanks! You're simply being smart about your advertising, and polite in that you're letting your neighbors know. You may end up paying a fee to a realtor who brings a buyer, though....
Or to push the closing out a bit if there is an issue in getting the mortgage comittment. The phrase "on or about" protects both parties involved.
Assuming your question was about if the taxes could be decreased, there is a senior tax exemption that can be applied to tax bills. It's very easy for your agent to see if that exemption has been applied to current owner's tax bill.
While lots of people do their home search online through sites like Zillow, the personal touch of a local agent who is aware of local market trends can't be overstated. I've set up listing appointments for clients several times, and have thrown in homes I think they would like, too, rather than just setting up what they send me. More than once, the home I added has been the one they ended up purchasing.
As soon as you can. That will give you plenty of time to get your home "market ready" without having to rush should you need to complete projects. A realtor will be able to guide you in ways to make your home desirable for prospective buyers in your market.
Sometimes with short sales, it's required that the inspection is done within a certain time frame after the seller has accepted the offer. However, just because the seller has accepted, doesn't mean the bank will do so. In this situation, you could be wasting your money, but it might make sense to do it before bank approval so you know that the house is worth the wait.
The bank will ask for a HUD and then see if the numbers make sense. There could be several HUDs requested before the deal is finalized.