csharp, both your 99 and 221 are short shank and the attachments for your featherweight will work on your 99. You can even get new ones that will work on them. The main thing to look for is that they are short shank attachments.
I found some Singer Lube at one of the area Joann's. Not all Joann's carry the lube. I just got it and haven't used it in my motors yet.