An option you have is to get your home sold at which time you will be in a position to write a contingent offer on homes for sale. The only drawback is bank owned homes and short sales will not accept a contingent offers. You will have to look at traditional sellers who may be willing to work with contingent offer. The better qualified your buyer is will help to convince a seller to take the risk of accepting a contingent sale.
Yes, but a better approach is simply to make an offer contingent on the sale of your current home. Or, ideally, put your house on the market. When you get a solid contract, then start looking for a house to buy.
You will find buying with an option to buy is difficult to find these days. There are many many disadvantages to you, the buyer, and only a few advantages that don't outweigh the disadvantages. Sell your house and rent until you are able to buy. The option to buy is a train wreck waiting to happen, so let it happen to someone else.