The neat thing about your question is that there are many definitions involved. Let us peruse the definitions of Knights of Labor, capitalism, socialism, and the AFL. Then we can begin to answer your questions.
The Knights of Labor was one of the most important labor organizations at the end of the 19th century. Their main goal was to institute the eight-hour workday for the working man of their time. Due to lack of organization, the group was permanently disbanded over time (even though its remnants still exist within some labor unions today). Capitalism is a system of economy where people and businesses control the wealth (as opposed to the government controlling the wealth). Socialism is a system of economy where the community controls the wealth (as opposed to the government, individuals, or corporations controlling the wealth). Finally, the AFL stands for the American Federation of Labor. It was founded at the end of the 19th century and had better leadership than the Knights of Labor. In fact, after merging with its rival and becoming the AFL-CIO in the 1950s, it has grown even more and still exists today.
I find your first question interesting because the Knights of Labor existed specifically within capitalism and was strategically against both “socialism and anarchism.” I am assuming you refer to the original acceptance of georgism by the members and their support of co-ops. In regards to the latter, the business is owned by the community and not by the individuals involved. This does sound like socialism, you are right. In regards to the former, georgism is also a philosophy of economics which is precisely about land. Basically, georgism says that natural resources should belong equally to the community members, but should be divvied up by the value created by each individual member. The confusion here comes in regards to both of these ideas’ focus on “community.” Still, remember that co-ops are simply one business unit that can exist within capitalism (as many exist within America today), and that resources (even within georgism) still belong to the individuals that help harness the natural resources. Considering that the Knights of Labor was specifically against socialism, they would definitely consider the reasoning above to be true.
In regards to your second set of questions, the AFL goals, instead of being many and varied, have always been considered “pure and simple” in regards to their organizational structure. In short, the AFL always focused on working conditions and wages. Period. They delegated political goals to their political friends and did not associate them with the organization itself. The AFL wanted to expand capitalism, not weaken it, and they used workers’ interested to support that idea, so socialism was far from the AFL’s goals, for sure in that they considered socialism “working class radicalism.”