I also transfer money each month into a different savings account for property taxes etc etc  Basically i keep personal and biz seperate. 

campaign=preIf you qualify, there are credit cards that offer no transfer fee and 0% APR during an introductory period.

If you do it you need to keep it in a separate account just like your deposit money and transfer it each month.

Can I transfer the property at any time, into the LLC or only right now during closing?

@Bob Burns You may want to look into the Uniform Transfer to Minors Act and whether/how it has been codified in your state.

So you first have to transfer ownership. 

Set up Zillow alerts for all small multifamily that "sell" (when properties transfer ownership landlords will be more open to talking) Network with small multifamily relators about buildings that are under renovations and will have multiple units coming up that need to be filled (problem) where you can "pre-lease" the unit and pay the landlord the 1st day it's available (solution) Remember the name of the game is "How do I profitably solve problems for the people I want to work with!" 

Once the final payment is made by me, what prevents the seller of just keeping the deed, ie: what holds then seller responsible to transfer the deed via QCD or warranty deed etc?

If they've rented the entire house as a group, then they need to figure out how to pay the rent, but you get the rent in full on the first of the month as a single transfer. 

Putting on my Project Management hat, we'd call that transferring risk.