I thought you wouldn't be able to see the photos here; so, that is why I made mention of my blog and just posted the photo without description here.
A: No, it isn't necessary to remove the feed dogs. I just gave that a test on my older Singer 66-1( I own two Singer 66-1 with back clamps) and was able to remove the pin screw from the ejector bar. The pin screw just cleared the feed dogs.
B: No, since there is just one way for them to be held in place, by the feed dog screw. Once you see and do this, you will have a better understanding( at least this is the case for the older models).
Realize that this is to help in removal of the wick screw. There most likely have been changes in design, but overall it should be the same.
An example of this change in design is found in my two Singer 66-1 with back clamps. One has wick screw and the other doesn't.
I just went to clean and change the wick on my older Singer 66-1, only to find out that it doesn't have a screw wick or even a place for one. Here is a photo:
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