Profit is locked in the day you close escrow ... you may not realize the profit at that time, but if profit is not "baked in" with a high degree of certainty at that point, it is not an investment IMHO.

I'm trying to lock up this property, but I don't know how much other developers would pay for it.

The tenants are not locked into a certain rate and you can raise the rents.

get your rates and terms locked in.. the area they will lend in.. etc.Note that Hardmoney is best secured with a local company they will know the market best and usually perform the best as well.

Set a date, place, time and let's lock it. 

That way just like you'd keep borrowing at, say %5, you might as well lock it in now and stretch the payback for as long as possible.

I hate having to re-key my locks. 

This would afford you flexibility in your expenses, as opposed to having a locked in loan payment. 

Should I be conservative and go with the 6 month offer or try to lock it down with the 4 month offer, the difference is about $10,000. 

Any time there was damage that the tenants did to my property (holes in the wall, broken locks, etc) the housing authority withheld rent until I fixed it.