TL,DR: What should I look for in a scanner for digitizing photographs from 10 to 80 years old, and various other media as secondary importance? Do you have any theoretical, or practical advice, or references to offer? If any further details are required, please let me know.
Details of media
I have a small collection (approximately 200) of photographs which I believe would be of value to those interested in the history, and architecture of Johannesburg. They were taken by my grandfather, and grandmother between 1950, and 1970. There are several other photographs which were taken prior to that, I think the oldest is around the mid 1940's, and a few which may have been from the late 1930's, photographer's likely unknown. These are what I am most interested in digitizing, and getting online. Many of the buildings no longer exist, and were taken for the explicit reason of documenting the architecture, and buildings, as well as land which has now been developed.
I have also got various photographs which are much newer, but mainly of personal interest. There are also various documents, books, news paper clippings, and other printed media which is out of copyright but currently unavailable online. Some of the books contain hand painted water colour. There are also water colour paintings themselves.
Unfortunately, I believe we no longer have the negatives, nor many of the slides which were also produced, but if any turn up, I would like to digitally archive those as well.
Everything which is out of copyright, or which is within our legal rights, we are planning to upload to a relevant image sharing, or collection site. (Barring those of purely personal interest.)
Personal/budget/time trade off limitations
I am not really concerned about the time, or manual involvement with the scanning process, my main concern is accuracy and quality of the scans. Technically, there is no budget available for this, so we are aiming to keep costs low but do not wish to completely skimp, and go into this blindly. Properly archiving the originals is highly unlikely to be an option, and some of it is to be sent off to other family members.
I have spent a little time researching my options, but this is all far out of my area of any theoretical, or practical expertise and gaining the theoretical knowledge is not something I will have time to do for a while.
I have no image editing skills, nor anything to manage colour calibration. It is highly preferable for the scanner to have good Linux support, and for any software to be available for Linux as well.
The storage of the resulting scans which are either still in copyright, or of only personal interest is something which is well within my skill set, file size is not too much of a concern at this point. (For those interested in the details, I am currently basing storage on an HP N40L microserver running Ubuntu 14.04, a long run UPS, and ZFS as the filesystem in either a mirror, or RAIDZ configuration. For local browsing and display, I am undecided, though might roll my own. Long term I do wish to have tape storage.)