Alternative Therapies Group Inc., BeWell Organic Medicine Inc., and Natural Remedies Inc. are once again presenting proposals for medical marijuana dispensaries in Methuen. The three companies went through the process last year, when they requested letters of non-opposition from the mayor and City Council. The letters, which are required by the state Department of Public Health, were granted to each of the companies but later rescinded as the city reexamined its review process for such facilities amid zoning and other concerns. This time, a selection committee is expected to whittle down the proposals to one successful applicant. That company will continue through the process and be eligible for a new letter of non-opposition pending further review by the City Council. A new letter of non-opposition could be issued to the selected facility in July.