You are asking the questions in what I would consider a reverse order. You should become proficient with the modeling software and if you intend to scan real human beans, the software associated with that bundle. Once you have a handle on the model creation, you'll likely have a good idea of printer requirements.

Even with that in mind, I'm a big fan of the Prusa MK3 printer for reliability and top quality printing. If you are not on a budget, you can buy a fully assembled and calibrated Prusa, or purchase the kit and learn how the thing goes together, in case you need to service it in the future. I can attest to the ease of assembly of the MK2s and a fellow makerspace member recently purchased the MK3. His description of assembly indicates (as expected) that the assembly of the MK3 is an order of magnitude easier than the MK2.

Users of other model printers will have recommendations for their model printer, I'm sure, as that's how this area of technology works. The key feature for your requirements would be overall capacity. You won't want a printer with a 150 mm (per dimension) build volume. Consider to measure a typical head and allow a few cm extra space and you'll have the numbers you need.

With every FFF type printer, there will be post-processing, to remove the layer lines. You can use a filling primer paint and light sanding and get good results in removing the lines. Silicone molding will pick up fingerprints on a glossy surface, so I know they will show layer lines easily. For your production method, a couple hours spent to smooth out the layer lines will go ten times as far in the final result.