My understanding is that mass in a black hole doesn't operate any differently at a distance. So if there was an earth-mass black hole in a tight orbit around the sun, it shouldn't have a significant impact on the orbits of objects in the solar system, even after it consumed the entirety of Sol's mass. Maybe Mercury would get messed up, depending on how tight the orbit is.
HOWEVER. Getting a black hole into a tight orbit - I don't know how that might happen. A black hole from outside the solar system would be coming in on a parabolic path past the sun. It would shoot right back out of the solar system.
If the BH managed to absorb enough mass from the sun, I would imagine that would throw off it's trajectory enough it could become captured into an orbit. On each subsequent fly by / through the sun, it would capture additional mass. This would reduce the period of the orbit.
In a situation like this, you have an increasingly massive object passing through the solar system in an irregular pattern. That can't be good.
HOWEVER. Getting a black hole into a tight orbit - I don't know how that might happen. A black hole from outside the solar system would be coming in on a parabolic path past the sun. It would shoot right back out of the solar system.
If the BH managed to absorb enough mass from the sun, I would imagine that would throw off it's trajectory enough it could become captured into an orbit. On each subsequent fly by / through the sun, it would capture additional mass. This would reduce the period of the orbit.
In a situation like this, you have an increasingly massive object passing through the solar system in an irregular pattern. That can't be good.