The melted lead is not terribly dangerous as illustrated by some friends who cast a lot and were tested. At least not the fumes.
However, if the temp is too high or the flame too hot, acetylene etc, it can vaporize the lead and this is not good.
Recycling lead with outside or with an open garage door etc is not likely to cause problems though sometimes the stuff coating the used lead can be bad.
Pour into muffin tins for small ingots or buy an ingot mould.
Kitchen range hood with a fan can be used to remove the fumes while casting bullets.
Dan