Stepmom and Mom in wedding...help!

Hi! I am newly engaged and probably not getting married til 2021...but still can’t stop thinking and planning ahead 😁

Long story short: my mother and I have had a poor relationship over the past few years. However, I’ve tried to include her in the excitement from the moment I got engaged and plan to include her in wedding festivities. But I have a stepmom who I have been a lot closer with. Honestly she feels like an older sister (lol! She’s a bit younger than my dad) but she’s important to me and it’s important that I honor her too.

Now...how to navigate them into the processional? Tradition says mother of the bride is escorted in last. Who do I have escort them?
I do not have a stepfather, my mother is recently dating someone. If they’re somehow still together in two years I guess I could have him escort her in? But probably not.
My mother has three sons in addition to me, and my stepmother has one son but he will only be 9 at the time of our wedding.

Thoughts? Ideas? Anyone with similar experiences?! Thanks!!