1. There is no way to tell if any eBay sale is legit unless you personally are the buyer. eBay is currently what sets the market for most comics on a day-to-day basis.
2. We will probably never know how many were printed. Although, being an independent publisher you may be able to find the right person to get you close.
3. First sale of 2018 was $2,300. Last sale was $1,900. Low in between was $1,730 and high was $2,500. Pretty normal fluctuation for a book of this price. Especially when you consider how many coupons eBay has put out this year.