I have never tested for GBS because it's so arbitrary. The stats on it are that it's unlikely in a homebirth with little or no vaginally disruption, that you are at real risk. I just weighed the risks against the benefits and made a decision. Everyone must do so! I did, however, take precaution a couple weeks prior to birth by taking Vit. C, liquid silver, grapefruit seed extract, echinacea, and garlic. Things that are natural antibiotics and kill bacterias.
As for the rhogam, there is really nothing alternative for this. You either need it and decide to take it or not, or you don't need it. I always have it on hand. My back up Dr. prescribes it to me during pregnancy and we just keep it if we need it. We've never needed it but I always test baby cord blood for the blood type so I know and even if we may have needed it based on that, I haven't decided if I would take it yet or not. I just gauge the birth and decide from there. You have 72 hours to decide and can walk into any ER and tell them you need it and they HAVE to give it to you. It's life or death type protocol and I haven't heard of anyone being denied. Given a hard time, yes, but not denied! And you can just say that baby came before you could make it to the hospital and you were checked over by someone so they don't go all crazy calling CPS or anything.
Both of those situations are strictly based on personal conviction, though! You have to decide how you feel about it and make those decisions on what's best for you and your family. So often, women just submit to the medical authority without giving these things much thought. I am all about investigating your choices and options!