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Some useful ideas there but with old photos you never really know what you are dealing with and it is a bit of a lottery. Definitely, scanning and Photoshopping is the safest way.
Scan it and then send the file to Digital Custom. I did just this last week and got the image back from them yesterday and it was like brand new. No glass, no weird areas where the glass had stuck and the color restored to original.
A conservator could remove the photo from the glass. It might be necessary to soak it in a water bath but I would leave that to a conservator since the drying process would be tricky.