The safest bet would be to create two entities, one for the tech biz and one for the baseball biz. If you wanna go cheapo make them propreitorships or if you wanna go more expensive then make them s-corps. Not really any need for corps here unless you feel liability protection is needed. If you are gonna have kids in the cage then you may want to consider the liability ramifications. I am the first one to hate when people call for liability protection for every damn thing but your accountant would most likely bring that up as well. The s-corp costs 800 smackers a year.
Also I had considered the home office expense as well because I do ALOT of work from home and my wife and I have 2 corps and one propreitorship. However we did not do it because we didn’t want to raise any red flags with the man. We already are pretty liberal with our business expense writeoffs and are content to take advantage of them without piling on the old home office as well.
If you are gonna undertake the tech instruction definitely open a business for that. You can expense alot of stuff. Again I am not an acct and you should talk to one.
Home batting cage is awesome. I cannot even begin to imagine how cool that would be. I have a 4 and 5 year old and am prepping them for that as well but it appears they like hockey more then baseball at this point.