I think if your son is going to public non-Waldorf school, then no, he won't be living a pure Waldorf lifestyle. But, who cares? It sounds like this is the thing that works for your family, right now, and that is what matters.
We started out 2 falls ago homeschooling using Christopherus. Things were going great, but my son got into a charter school (non-Waldorf) and we decided to give it a try. It worked out well for all of us, at the time, and he continued the rest of the year there and started back there this fall. He's now back home, but that's not the point of this story
Now, we were never the purest of the pure Waldorf families, but I definitely did find it more difficult to provide a Waldorf childhood for him when he was at this school. Things like you talked about- computers, videos in school, friends whose families did not share the same philosophies, plus just the very busy nature of his days- were very different from our time homeschooling. I swear, I think he was the only child in his school without a Nintendo DS and he felt left out, and we heard about it. A lot. But it was overall a good experience.
We did try to maintain some Waldorf-y rhythms at home, but the fact was that he was at school more than he was home (awake anyway).
I am trying to type super-fast while the kids are brushing their teeth, so I hope I'm making sense. The most important thing is your happiness and your family's happiness, not some Waldorf ideal that is unreachable to all but a very few. Your son is happy, you are happy, that is what matters.
By all means, I would try to create a Waldorf-y homelife for your littler ones. That would be a great gift to all of you, I'd think. The key is simplicity, I think. Bake one day, garden one day, paint one day....
My time's up! Best of luck!