FHA wouldnt be used by you as an investor. Your buyers might need FHA financing and this where the 90 days seasoning will come into affect. You'll need to be on title 90 days before selling. Some conventional lenders have picked up on seller seasoning too.
Cash out seasoning is 6 months if you plan to get a conventional mortgage. You can own up to 4 financed properties. So if you used your own funds to buy the property then you'd need to wait 6 months if you wanted to get that cash back. If you used a private or hard money lender to acquire(that secures a 1st lien) then you could pay back that through a rate/term refi and there is no seasoning. However, if you want any cash out beyond paying off the 1st lien then you'd have to wait.
The cash out restriction is only for conventional loans though. There are commercial and portfolio loans that dont have seasoning requirements and dont have a restriction on how many properties you own. These loans will not be 30yr fixed terms though, more like 20yr amort with a 3-5yr balloon.