Often, contracts have a seller representation that the major systems (e.g. heating system, plumbing) are in working order.

My fear is that, even if peaked, there is still some time to earn some profit in Nashville and then get out before the market dries up and Tampa is just much more of a question mark.  

While there are still some properties that ca be profitable, other areas might be more desirable in this area.

Besides, I'm a newbie and many investors disapproved of this deal the last time I posted it at BP.A few days later, to save my friend from an unprofitable deal, I ask her to buy a house for herself since she's not into it for profit but to seek a bigger shelter than her condo.

and if renting for short-term is even profitable?

If you were thinking about moving back in so you could access the profit through the primary residence exclusion you'll only be able to prorate it between the times of "qualified use" (as primary) and "non qualified use" (as rental).  

Would the seller want to partner with me : where I fix it and sell it and we split profits? 

Well for general considerations about whether to have an LLC for rental properties or not, check out-https://www.biggerpockets.com/renewsblog/2013/08/1...Read through the comments too as there's a lot of info in those too.One major comment would be, and an accountant or an entity specialist should bring this to your attention, is that rental properties and flips are two different things as far as taxes....passive income vs active income...and those should not be mixed under one LLC.

Property is located in Florida near major city.I am able to purchase the property but I will need to a partner or investor to cover the rehab portion.

Sounds to me like your first move should be to sell your NJ rental and invest the proceeds somewhere more profitable.