I agree there isn't enough information out there about GBS. You definitely can have a homebirth is you are a known GBS carrier, in fact I will be pedantic and say that any pregnant woman can have a homebirth no matter what her condition is, it is just whether she will receive support in doing so.

It's such a transient condition that just because you test negative at one gestation, it doesn't mean that you will test negative at the another. Certainly in your case where you were a known GBS carrier in your last pregnancy, this should not affect your care for the next pregnancy and you should be able to 'have' your homebirth. The concern lies with active GBS positive status at the point of labour and even then, you have to weigh up the risk of subjecting yourself & unborn child to prophylactic use of antibiotics over the small risk of GBS having a detrimental effect on your baby.

Yes, we do hear about babies doing badly due to GBS infection but the truth is, in any aspect of health care, zero mortality is not something that can be achieved.