Hi Johnnymms,
I caught two swarms last year, from what I believe to be the same feral hive. I did not have any, none, zero, nada, zilch, bee keeping experience, and still do not have much. I put the swarms in a plastic tote tub over night since it was evening when I caught the swarms, till I could run to our local lumber yard and purchase hives the next morning. I put the swarm in a hive body the next day and about 10 days later the feral hive issued a second swarm and I had the same experience all over again, including both nights being during a torrential downpour and the next day being sunny.
That is the story of me starting bee keeping in a nutshell, I still just have the two hives and they seem to be doing well. I have just pretty much let the bees do their thing I am going to test for mites, and I am not opposed to some of the natural treatments. but I have done nothing as yet.
I did set two single deep hive bodies out at my yard and hope to catch a swarm if possible. I am thinking that it may be from one of my hives. If it should happen that I get the opportunity to split my hives first to make increase then I hope to catch another feral swarm or someone else's swarm which I would just put in a hive body and leave in my yard and then keep an eye on them hopefully.
so long story about my experience so far, to answer your question I would not really fear putting a swarm in an existing yard if I was to catch one.
Happy Home.