I'm not familiar with the Singer Tradition; maybe someone else is. I clicked on one of the listings for the stitch-in-the-ditch foot and she listed all of the Singer machines it would fit. Instead of the Tradition name, look for a model # on your machine and see if it matches up with something on her list. Also, she has a close-up picture of the foot; see if the back of the foot looks like the back of the feet you have.
The feet you get depend on the specific needs you have. My Bernina has the "stitch-in-the-ditch" type foot and it does help me stay in the ditch; still, I'm imperfect enough with it that I don't like to do that kind of quilting if I can help it. The black piece in the middle rides "in the ditch" to help you stay where you want to be in the seam.
A walking foot is recommended if you want to do straight-line quilting that is not in the ditch or for gently waving quilting lines. It works on feeding the top fabric at the same rate as the backing fabric to prevent puckers and wrinkles. It is used when sewing on binding for the same reason. There are generic walking feet on the market that will fit a variety of machines. Some of them are good, some are very cheaply made and not so good. Try looking for one made especially for your brand and model of machine; they are often better quality than some of the generics.
A darning foot is often used for free-motion quilting. This foot "hops" between each stitch, allowing the user to move the quilt sandwich freely.