Scarlett alot of those things will crater the deal if they are in writing and are delivered to the lender (the first) regarding the short sale. At the beginning of the process if the first knows you are gonna hold back cash for the second they will not authorize the deal. Having the experience of knowing when to put that into play and when not to is important. Similarly doing things like paying out of pocket expenses for the seller is also something that could be considered in a very negative light by the short selling lender. So can you put them in writing as an addendum? Well yes you can. You can also not deliver them to the short sale lender but again, you walk a fine line at that point. Your agent should also know what to ask and what not to ask in order to get the deal done.
Also there is a familiar theme here which is, many a buyer is frustrated with what is out there and how difficult it is to get something of quality. However when they do have that opportunity but are forced to do things like the previous poster wrote about, many are reticent to do that. So at this point you are frustrated and it is understandable. However it is also hard to predict how you or any buyer would react to undefined parameters and/or paying out of pockets for a short selling homeowner when it is crunch time. Obviously it would depend on how much you wanted the home.