I would like to thank everyone for their advice, opinions, suggestions, and support.
While I generally agree with those who've stated that it is distasteful to withraw an invitation to be in a wedding once it's been given, I do have to take my own personal health and well being into consideration as well. This situation has been extremely stressful and has been a burden on DF, meself, and both our families.
The issue has now been resolved and the bridesmaid in question and the groomsman (her husband) will be attending our wedding just as guests.
Once we sat down and discussed it, DF and I still felt very strongly that while we value thier friendship and wanted them to be in the wedding party to help us celebrate we do not want anyone to feel uncomfortable with thier role or participation in our wedding. We would prefer to have our friends be able to attend as happy unstressed guests and enjoy the day with us, rather than stressed out schedule and financially constrained attendants.
It is a decision that is the best for everyone involved, and we are happy and relieved that it has been resolved.
Thank you again for everyone's help and support!
You guys are the best!