Take my advice with a grain of salt
Goal 1: Buy - Buy with 5% down on each purchase and do over 6 deals a year: Assuming you are financing with bank, 5% downpayment is for FHA loans and I believe it's for only primary residences. Many banks will have a condition that you have to live at least 12 months in your primary residence.
While living in your primary residence, if you choose to purchase another property, it will be considered as 'Investment Property' and generally, you have to put 20% down, and for multi-family i believe it's 25% (Again assuming that you are financing with banks)
Goal 3: Refinance : Personally, I would run my numbers little conservatively here and consider my LTV would be 70% to 75% just to be on more safer side. Yes general seasoning period is 6 months and yes there are few lenders who can do it after 3 months too but interest rate might be little higher comparatively.
Goal 4: Rent : If you financing with the bank as a primary residence, usually there will be a condition that says 'you'll have to live in the property for at least 12 months. But you can house hack though.
To put 5% down on 6 properties a year, you can even choose to go creative financing route like 'Owner financing', 'Subject to' etc
Hope that helps. Good Luck !
