Yes, you can include just about anything you want in an offer. That doesn't mean they will accept it, but the only way to know if to make the offer.

Of course, if you bid on a FSBO and already think it is overpriced, and want to a RE fee in, and have a sale contingency, you are likely to be pretty far apart from the seller in terms of expectations. Typically, people do FSBO because they are trying to maximize their profit.

Please respond to people reading your other thread, we like feedback from the OP.
Yes, you can make a contingency offer, just as your buyers have. I would not ask in advance, I would present to the seller your full written offer, with all terms. I won't listen to a verbal offer or one in piecemeal. I need to see the full picture before I know what I will or won't do or how to respond to each item.
If you feel unable to deal with the seller directly you can hire an agent or attorney to make the offer, but don't expect the seller to pay for one to receive your offer.
You can directly give the seller your support docs for your offer at the time you make an offer. Your problem with using an agent is the irritation to the seller since they already have it FSBO for a reason, then your agent appears at their door saying I have a buyer, but first sign this agreement before I present. The seller already has plenty of agents knocking on their do, and most say they have a buyer.
One more agent with the same story is not endearing...

Good advice by both responders. I'm not laughing at you but I did chuckle. It doesn't seem like so much bs anymore when you're the one who wants to offer with a contingency. Good luck and hope it all pans out.

I think you misunderstood. I did not think a contingency was bs but the fact that they will not put their house on the market until they find their dream home.

I found that most FSBO would gladly pay 3% commission to buyers agent, just not the full listing commission. Also the buyer could pay, if you do the math the $ come from the buyer packet anyway and just routed through the seller on the HUD statement

I think then most of us misunderstood, as you didn't elaborate and clear it up. The thread ended up being about contingencies.