I need a legal letter from a US lawyer for an RMG license

I and my business partner are in the process of setting up a prize competition business, called a contest in the US. We are UK registered business but want to market to the US using Facebook. To do this, Facebook requires us to complete an RMG license and as part of this license, we need letters from a solicitor in each country stating our website/competition is legal under the laws of that country. We have a letter from a UK lawyer as our competition/website is legal in the UK. After researching the US, the law appears to fall under the same rules as the UK apart from in 5 states to which we will not market too. So we are seeking a solicitor who can look over our website and provide a letter for the RMG license.