Are these basic PhotoPass shots that you want reworked? Cell phone selfies, etc? Have a sample of a shot? I can work a portion of one just to see if it's what you're actually asking. I work on a production workstation Dell M6800 32 GB Nvidia Quadro 4 GB specifically for handling HD, 3d graphics, and processing large video and images.
I do recommend just handling it yourself using some quick & easy masking techniques in Photoshop. You probably know best what you want anyways. A lot of students may do this for you for free, as part of their portfolio experience.
It can be extremely time consuming, depending on how good of a job you want done. I've been doing this for several years both on video and photos. The fastest is to just mask the subject out of the image and replace the background. If you want to preserve the background but remove one individual, that can be an imperfect art.
For example, let's say you don't like the messy background. A basic photoshopper with some experience can do this within an hour. If you have no experience, it would take several hours for you to learn the basics.
It really depends on the shot. If it's an unplanned shot, you're dealing with many variables - including awkward lighting effects, individual hairs strands flying around that need to be preserved or re-drawn, motion blur, grain -- all of that adds to the processing time. In the example above, the original shot works well because we only need to work with relatively hard lines.
I've done motion graphics/greenscreen and compositing work in music videos for several years. I've run into a lot of issues, so getting the shot right the first time (or discussing with editor beforehand) is always my suggestion. However, I have had to "save" some shots and this skill comes in handy if it's important to process a particular image.
Based on that, I recommend you do it yourself in the most basic way possible. If you want us to take a look, you can email me or post here.
EDIT: Stuff like this is also what drives me nuts about
Disneyland. THey don't allow photographers or film producers to bring in ideal equipment for getting shots right. If they catch you doing multiple takes and trying to direct or reposition the Characters, you get pushback for it. If you buy Photopass, the image is already processed and you can't access the raw directly from their camera. They make it HARD to get perfect shots.