The holdover tenant was caught on my security camera in the front yard yelling at her boyfriend saying all he knows how to do is smoke and roll blunts all day. 

All monies paid up front -1st, last, security deposit and $400/mo for utilities.What are the pitfalls? 

I would accept under the condition she pays you 1st & last months rent up front + security deposit.Good Luck! 

If the tenant is good and you want the security you always have the option to renew at the same or higher rent.

sa=...Question 2, you could try and sue but id take it out of the security deposit and move on.

They are securities but backed by real estate and commercially evaluated real estate at that. 

Then I'd like to  make the rest of my own contribution as employee of ($19,500-$6645) = $12,855 to equal the maximum allowable of $57,000 (37500+12855+6645) If this is how this works...I'm assuming 57k is max across everything...My question is, since my main job has already payed both the employer and employee portion of the social security tax, will I only have to pay medicare taxes on my 2nd business?

How do you collect a security deposit for tenants that currently live in one unit of a multi-family I'm scheduled to close on in two weeks?

im not sure which type of brick wall you are referring too, but framing wont vary much on cost for the same wall that is load bearing verses non load bearing. its more a function of materials and complexity. as for bundling, anything is negotiable. in general, i have found it much easier to negotiate with contractors for bigger versus smaller jobs. put yourself in their shoes, a bigger job has more security and profit. i would be willing to accept lower rates for a project that will take 4 weeks versus one that takes 2 days. 

So if your $1,000,000 oceanfront property gets swept out to sea in a raging Nor'Easter, you can rest secure that you'll collect $250,000!