Will you have a paying job as well, or will you be able to devote all of your time to your farming? Congrats to you and your family. I think that multi generational family living can provide far more benefit than any inconvenience that may come of it. My suggestion to you: start slow. I have no experience with horses, though my family did have them when I was growing up. Looking at horses from my perspective is that they can become a very expensive hobby. Great if you have the money to put into them, but... if your personal economy does a tail spin, you may regret having them. A lot of your planning is going to be entirely dependent on the piece of property you end up with. It would be helpful if you put your general location in your profile.
Will your parents be helping you with the livestock and gardening? What tools do you have at your disposal now? I think the most important skill you can work on while waiting is to learn how to use power tools, and be sure you have a well stocked work shop with all of the basic wood working power tools. With a little ingenuity, and the right tools, you can build a coop, chicken tractor, shed, green house, and just about anything else you decide your property needs. IMO, the land (soil quality) and sun exposure are the most important part of a homestead. A house, while necessary is less important. The house can always be improved. But, if you have a wet piece of land, lots of clay, heavily wooded, stripped of topsoil, or otherwise difficult to work piece of land, you are going to be fighting every step of the way.
Start with your local library, and spend your time reading about all of the topics pertinent to your homesteading effort. What kind of animals do you want? How much work does each species entail? Can you think of any spin off profit making activities you can add to the homestead? Want goats? How bout selling goat soap, goat cheese. Ever milked a cow? Will you be hand milking? I suggest you visit a local farm, and give it a try. Ask lots of questions as you help the farm owner do chores for the day. Have you ever processed a chicken? Again, valuable experience can be gained by visiting someone who does their own processing. Read all of the books pertaining to gardening and farming that you can get your hands on. Here are a few of my favorites to get you started.
https://www.google.com/imgres?imgur...ved=0ahUKEwi7_9WhpM_QAhVR6mMKHQ3dBrIQ_B0IbzAK
http://www.ebay.com/p/?iid=152258625134&ul_noapp=true,true&chn=ps&lpid=82,82
https://www.google.com/webhp?source...xTSpzTIostQQcS0sy8otC8p3y87P983IqAb4_gRArAAAA
https://www.amazon.com/Small-Scale-Poultry-Flock-All-Natural-Approach/dp/1603582908
In the mean time, while you are working on selling your home, do what ever it takes to get top dollar. It's amazing how a couple of cans of paint, and purging any clutter from your home can both be freeing to you and increase your assessment and sale value. Start frugal living now. One of the biggest money savers for me in my home is home made laundry detergent. I made a year supply for around $5.00. I'm finally down to my last quart. Time to make some more. It's idiot simple to do. To save money with your poultry, use dry leaves (if you can still get them) in the coop for bedding. IMO, leaves are far superior to shavings for bedding. They are also more useful in the compost and garden when you remove them from the coop. If not already doing so, switch them to fermented feed for about 30% reduction on your feed bill as well as giving them superior nutrition.
). The area has a few good barns already, so I'm not honestly expecting the lessons thing to be more of a "small side hustle" for beginner kids whose parents aren't interested in the pressure of the big show barns with long-term lesson contracts. The most promising property right now used to belong to my riding instructor in high school, so that's pretty neat. 
