Personally I doubt you would have much success with 5 parallel offers. If I had someone submit something like that, I would counsel my client that this was not likely a serious buyer and wasnt really motivated to buy their property. Most people with a good piece of property would probably react the same way and what you would likely end up with is a lousy piece of property at a good price. Certainly not the optimal result if you are looking for a nice place to live. If you are looking for an investment there are better ones out there than real estate and will be for a long time to come.
The best way to handle things is to find the house you like best and negotiate firmly. You can always walk if you dont get what you want, but at least you will be taken seriously. Trying to play the strong arm 5 parallel offers is not likely to provide optimum results in my opinion. The same goes for verbal offers. Unless you are willing to put it in writing it’s pretty much an unqualified frivilous offer. There is alot more than price involved in evaluating an offer and a verbal price offer generally will be met with indignation.
There is a right and a wrong way to handle business. Much of what you are advocating is vengeful, mean spirited and most important UNNECESSARY!
Find what you like, make an offer and move on if you cant get what you want. Its that easy and will work much better. No one wants to be involved in a business transaction with an a$$h*le. Trying to be one will result in the seller psychologically charging you a price for being one.
BTW, if you choose the 5 offer path there are so many outs for a buyer in the standard purchase agreement that you could go into escrow on all 5 and walk away without financial penalty on any of them. Not an ethical thing to do but the CA RPA (California residential purchase agreement) protects you automatically for at least 17 days unless negotiated differently and until you release your contingencies in writing).