Short answers, pulled from the story.
The Loyal War Governors' Conference was a political meeting of thirteen Union state governors held on September 24 and 25, 1862, at the Logan House Hotel in Altoona, Pennsylvania. The governors gathered to discuss state troop quotas, support for the Preliminary Emancipation Proclamation, and the conduct of the war effort.
Pennsylvania Governor Andrew Gregg Curtin organized and hosted the conference. He sent a telegram invitation on the 6th of September, 1862, to all Union governors, calling on them to meet at a point in the border states to discuss the war effort.
Lincoln feared that releasing the proclamation without a military victory would make it appear as a desperate last measure rather than a position of strength. He also worried that border states still practicing slavery might secede. The Battle of Antietam on the 17th of September 1862 gave him the victory he needed, and he issued the Preliminary Emancipation Proclamation five days later.
Governor Augustus Bradford of Maryland was the only governor to withhold his signature from the final address. The source attributes this most likely to Maryland's status as a slave state at the time.
General George B. McClellan was relieved of command less than two months after the conference. Several governors, including John Andrew of Massachusetts and William Sprague of Rhode Island, had openly criticized his leadership during the Altoona meeting.
The Logan House Hotel was built in 1854 by the Pennsylvania Railroad and was known as the Mansion in the Wilderness. With 106 rooms, gas lighting, and hot running water, it was considered one of the most modern hotels of its era. The building was demolished in 1931 and the site is now the Altoona Post Office.