I am a little under 8 months till the big day

I have my dress, venue, cake, photographer, flowers, two special items and a few little things all taken care of. We got engaged almost a year ago and I chose my bridesmaids and MOH in January while finishing my last semester of college. The issue: One of my bridesmaids I have barely talked to much since I moved away in May, well actually we haven't been "best friends" like we were for three years since about March since she got obsessed with a current boyfriend (and I am so happy she is happy) The problem is I have gone above and beyond to keep communication, gone to visit mutual friends and she ditches everyone to go to see him, and broke promises of coming to visit me where I live now due to "her boyfriend did not want her to drive 3 hours" to see me. To mix it all up even more I have a new friend that I have known for about a year but we have clicked right away and are super close since I have moved and I would love to have her in our wedding, but I already chose everyone in Jan. Part of me wants to replace the bridesmaid with my friend from home because I honestly do not know if I can trust her. I can keep going but it's so much confusion. I just do not know what to do about her and I need to figure it out asap, any advice on removing someone from the bridal party and putting someone else in new?
Also Bridesmaid Dresses :
No where out of 4 different states where myself and my girls live carry the dresses I LOVE in the store, though can order it. Is it save to be measured and then order the dresses if you love them online?
Thanks for future help