How can i include my brother’s wife?

So here’s the backstory: I just got back from my bachelorette weekend with only my 4 bridesmaids. It was supposed to be 5 bridesmaids BUT one of my girls forgot my wedding date and booked a trip for her and her husband that leaves on the day of our wedding. I found that news out in mid-July which obviously stressed me out and got me emotional. 2 days after that, I realized nobody in my wedding party had even looked into any of the airbnb’s or hotels I recommended 3-4 months ago when I stated I wanted my bachelorette getaway from August 9-11. So I planned my bachelorette getaway by myself and paid for it with the girls paying me back. They decided to book a party boat for us to go out on around lunchtime. I didn’t fully enjoy myself and got sunburned really bad. I’m back completely regretting my weekend and to a text from my brother saying that there was a problem with my brother and SIL. I call her and the problem is that I didn’t include my SIL in my bachelorette party like she did me 5 years ago in Vegas. I was an outcast during her bachelorette weekend anyways. The only time I received a text from her since we got engaged (April 26, 2018) was THE DAY we got engaged congratulating us. Since then, she hasn’t called or texted me to even see how I was. So 1) why would she even pop into my mind as a person to invite and 2) I planned this getaway in less than a month so even if I had thought to invite her, I doubt she would’ve been able to take off from work and book her flight. Am I in the wrong here? My brother (who is my absolute best friend since I was a baby) is siding with his wife and thinks she should’ve been included. So, if she still wants to, how can I include her in our wedding that doesn’t involve her being in my bridal party? She is NOT religious in ANY aspect! I have my brother reading some bible verses and doing a brother/sister dance with him. We have 76 days left until our wedding.