Just as a warning, those grand old Victorians can have some pretty nasty demons (and of the metaphorical variety, not the metaphysical ones) lurking underneath, and that goes moreso for your idea. I don’t know if the research you did included converting a much older building into a hostel vs. something more modern.
Since a B&B generally does not require much in the way of construction on an existing house (other than usually the kitchen), nor does it generally have more bedrooms than the original design (meaning it can be “grandfathered” in), they can likely get away with a lot, building-code-wise, that a house converted into a higher-occupancy hostel cannot.
And for decent reason; increasing the occupancy of a house puts greater stress on the infrastructure vs. the original design, and it could involve a complete rip/replace of the entire plumbing and electrical systems (and we won’t even get into the lead paint; unless the lead’s already been remediated, those grand old houses absolutely have lead paint throughout, which makes construction that much more fun, since you don’t want to kill the construction workers with lead dust.)
Not saying you should give up on your idea; I think it sounds interesting. Just that you might want to find somebody that’s familiar with commercial building codes in the state (better yet, one specifically familiar with the rules for at least hotels, even if there isn’t any such thing as a “hostel specialist”) to inspect the property and your plans for it before you commit. (I say this because a regular local property inspector that normally looks over a house before buying is not necessarily going to have that expertise.) This sounds painful because it will involve a lot of up-front cost, like paying an architect to draw up structural plans for a building you may not end up buying, but it’s something I would do in your place.