IMHO YANBU
You sound like a wonderful Grandma! Snuggling in bed, listening to owls, supporting your DIL with breastfeeding. And you clearly have a lot of respect for your DS and DIL.
I’ve also brought my kids up like you (co-sleeping, breastfeeding, taking them wherever I go and letting them sleep in the pushchair when tired etc). I’m also vegetarian. A fear of mine is that my DS’s may have kids with women who are the other end of the spectrum. I’d have to respect them, of course, but I’d find it heart-breaking if, for example, I could hear a child crying itself to sleep etc.
I don’t think you’ve done anything wrong. You took him to the couch in order to respect their no co-sleeping rule. Your DIL does sound like she’s struggling and it’s making her quite uptight. It sounds like she doesn’t have a lot of support from your son if he works such long hours.
While it’s so important not to undermine parents’ way of doing things, which you clearly know, children should have their own special relationship with grandparents. While my relationship with my mother has never been easy, she’s been a wonderful grandmother to the kids (snuggling in bed together, watching favourite tv shows, playing games etc) and it’s enriched their lives so much.
Don’t give up on your relationship with your grandkids. Keep up the video calls and visit whenever you can, even if you do have to stay in an hotel. When they’re older (e.g. when they have their own phones and can stay with, or go away with, you without their parents), it should get much easier.