For a flatbed scanner my current top pick is an Epson V 800 or 850.
Decide on your photo management software first. I would also think through very carefully your file naming scheme and also your cataloging/keywording structure. My choice is LightRoom for many, many reasons described elsewhere. Also decide if you plan to scan at archival resolutions or not. My feeling is that scanning at as high a real resolution as possible up to the limits of the film/photo is much better to avoid having to redo the project in a few years.
Another option is to set up a high resolution copystand with a really top end digital camera tethered to lightroom. Peter Krogh’s book on digital scanning is a good primer on that and his DAM book is IMO necessary for anyone approaching a major family archive project. http://thedambook.com/the-dam-bookshop/
I am actually meeting with a photographer with a 56 megapixel camera today and we are going to do some test pictures of some of our larger format items.
If you are comfortable sending items to a scanning service then the top pick IMO is http://www.digmypics.com mostly because they do evrything in the US. I do not want to send my stuff off to India for scanning!
A good overall resource is https://dpbestflow.org
Library of Congress also provides a lot of info on how to determine optimum scan resolution for various types of media.
For a quickie look at the project, perhaps for low resolution scans you can rent both slide and photo scanners from this place. https://store.ezphotoscan.com I have not used them but they are on my list to try for scanning the huge collection of slides we have to determine which ones we need to do at the high end 6400 dpi resolution with the expensive Nikon scanner that is ancient and on its last legs.
I’m in the middle of a similar project but my items range from collections at the historical society and my own family stuff. The collection I am working with consists of something like 25K color slides, about 19K prints, 1500 glass plate negatives, about 15K color negatives and around 100 old historical scrapbooks.