That's certainly a valid consideration. Undercuts are usually avoided in molding. Do you have a plan of attack to deal with that aspect of your project?

Back to the 3D printing part. If you do not require engineering level precision, a model printed in ABS plastic can be acetone-smoothed to give a very very smooth surface. Using 100 micron layers (0.100 mm) will reduce the irregularities on the surface as well. If you take a set of contours over 8 inches that have 200 or 300 micron layers, it will look like topographic maps but in real dimensions, not just visually. Of course, a 100 micron model will take three times as long, but I don't think that's a factor if surface is your focus.

Another aspect to consider in your search for a printer, beyond ABS printing, will be a heated bed (required for ABS) and a complete enclosure to prevent warping. ABS really likes to warp over large flattish models. Heated temperature controlled enclosures reduce (and maybe eliminate) that warping. If you use a glass bed, I'd recommend Wolfbite for ABS as it grips like crazy, yet releases at a touch when the bed cools.

Just to make things more interesting, there is also 3D printable casting wax. You can avoid the ABS warping problem, and maybe have easier post-processing with wax 3D printing. A heat gun, a soldering iron and you're good to go. Minimal requirements with respect to temperatures and warping for that material. I've attempted it, but ran into unrelated problems that had nothing to do with the material and have since forgotten the project.

So many options for your objective and your budget is quite generous.