Transfer property from one LLC to another LLC

[Leo Aso]

I'm in the process of buying two vacant lots in FL. I have to transfer them from an LLC with multiple members to another LLC. Essentially, I'm buying out my partners and transferring the lots to my own LLC.

1.Do I need a purchase and sale agreement for this type of transaction? Draft with an attorney or create my own? 

2.Also, are there any tax advantages if I keep current LLC and just remove the members?

3.What are the cost of transferring lots into a new LLC?

4. Let's say I sell the properties in couple years. What are the capital gains calculated based on (sale price on purchase agreement)?

Thank you!