Can we talk about my hair?

I think your natural colour looks good and suits your complexion. Some natural browns are really 'flat' looking, but yours doesn't seem to be, it looks like you have some natural highlights.
If this was me, I'd get my hair cut a bit shorter, dye over the blonde ends with a warm brown for a year or so and when the shaved bit grows out, then go and get the foils done and go back to blonde if you still want to. That's going to be the least obvious and least expensive option.
But then I'm also in the camp of not trying to 'hide' things especially when it's been major surgery, if I wanted blonde back, I'd just do it and if anyone commented I'd be saying "Oh that's where I had a brain tumour removed"...that shuts people up pretty fast!

I actually did go back to my natural colour about 10 years ago, I was blonde as a child and have had blonde foils since then, then I found that my natural colour was a nice dark blonde with auburn highlights and I decided to stop dying it...yes then after about a year I discovered a shitload of grey hair and that put paid to that idea...back to the hairdresser and back to blonde highlights, no way was I going to have visible grey hair in my late 30s! Shame I was ready for the change and ready to stop colouring my hair, but definitely NOT ready to be grey.

Your hair is GREAT! That ombre look takes some time to get used to on yourself, but when others look, it looks good. Do you have a picture of yourself as a blonde? I know we tend to go with what we are used to seeing in the mirror, but your picture looks really, really good. I'd like to see a picture of you blonde before I say go blonde!!

Although I agree that your natural color is beautiful, you say you hate it and I would never ever keep a hair color I hated when it can so easily be changed. I would wait 2 weeks for the shorter hair to grow out a bit more. Then I would get the foil highlights - there is no reason a stylist couldn't get into the shorter parts, just like when they do bangs or shorter hair on the sides. I hope you have access to a better stylist, that makes all the difference. I'd be angry that the one in January didn't even listen to what you wanted.

For touch ups, try some Preference Root Rescue (only $6 a box at Walmart) or a similar product. It's applied with a comb/wand thing that helps you control where it's applied so that you can get close to the roots. My daughters and I have had very good luck using it and matching the color close enough that it blends in quite nicely. I have dirty blonde hair and get it lightened and brightened by a stylist and love it that way. You can always easily go back to brown if the highlights don't work out, but if blonde makes you happy, Go For It!

I am going to say get a better stylist. A better stylist who listens makes all the difference! No way would anyone be doing the ombre look on me if I didn't want it. I also like the idea of a warm brown tone for you hair as well. Is you hair layered? You could also look into doing that for more volume if that is something you are looking for. It might also help make the parts that are growing out less noticeable.