It is always advisable to seek the advice of a lawyer who deals with the music industry to answer any type of legal questions.
Having said that, myself and thousands of other people have published songs that were created using BIAB software. As far as I know there have been no lawsuits as a result of those actions.
The issues of copyright are about as complex as it gets and no forum has the expertise to guarantee all your questions will be answered correctly.
As with most things, nothing normally happens unless there is money involved. Make a song with BIAB that generates millions in revenue and things could get pretty complicated.
Billy
THIS! This right there is your answer. Full stop.
My practical advice is just do your thing and enjoy yourself! Statistically speaking, you are unlikely to ever generate enough money with your songs to get the attention of corporations and their lawyers. If you happen to get lucky enough to generate big money you can then afford lawyers to help you figure out how to hang onto it!