This isn't as solvable of a problem as you probably think it is.
As Sander Huisman pointed out, you don't typically need to include earth in the calculations of the orbits of other planets to get decent predictions well into the future. But if you were to demand to know what the difference is, you'd actually need to calculate a huge, chaotic n-body problem. And if you've ever looked at n-body simulations, you'll know they're not simple by any means.
It'd be instructive to look at just a two planet system and try this. You might find for example that uncertainty in the initial positions and velocities of the planets (due to measurement error) overwhelms the slight difference caused by the deletion of a minor plant in your simulation. I'd claim that it most certainly would have to after a certain point in time.
In short, I would not be confident that what you've requested is possible until an astrophysicist said it was. And even there I'm sure there'd be a ton of caveats about what the simulation "meant".