1031 required Total price of replacement properties

[Ray Slack]

I'm selling a rental property for $550k and holding $130k in seller financing for 1 year with a balloon payment next year. I bought the property for $80k.   My questions are these:

1. Would I need to buy replacement properties that totaled $550k ?  or my Basis in the property of roughly $470k ? (rental is vacant land so no deprecation)  Or would the $130k be boot next year when the balloon comes due?

2. If I buy 3 properties that Total the $550k or whatever it is that they need to total and then down the road sell just one of those properties and wanted to 1031 again would I only have to invest the sales price of the property? for instant I would buy 1 property for $400k and 2 properties for $75k to total $550k ..  Then in 2022 I want to sell one of the $75k properties for say $100k.. I would then only have to purchase a new property of $100k or over correct?