Yes of course you can buy, and no, you have no legal obligation to pay any extra money, unless you signed otherwise, which is unlikely. Agents have a saying, "No one owns a buyer."
In New York State, buyers rarely sign agreements concerning commissions with a buyer's agent. Rarely--not never, just rarely. In other states, buyers are more likely to sign commission agreements with agents. [The NY State agency disclosure you signed is Not a contract, it's just a disclosure.]
If you did not sign a buyer's agreement to pay a commission to an agent, you have nothing to worry about. Any commission concerns are among the brokerages and do not concern you.
It is possible, however, that the seller's agent will hear from your former buyer's agent demanding some share of the commission.
Therefore, you should tell your new buyers' agent, if any, the history of this situation.
Also, you could ask the new buyer's agent to show you the house again, that you want to take a second look. That helps establish your new buyer's agent's relationship between you and the property.
If you buy the house without any new buyer's agent, as an unrepresented buyer, the seller's agent might arrange to share commission with your former agent anyway.
Commission sharing occurs among brokerages as specified by the seller's listing agreement and the agreements brokerages have among themselves. These are contracts that you, as a buyer, are not a party to in any way. Therefore what exactly happens to that commission is not something you control, although the outcome will be disclosed to you by closing time.
Licensed Real Estate Salesperson
New York, NY