Similar thing happened to me with a lady who moved in opposite - I was 6m pregnant with my third, and she had ds1 a similar age to my ds2, plus 6w old ds2. We had some great times together with the children, but it all got a bit much...
The copying went as follows; car (same model and colour TWICE), front room painted same unusual colour, going to the same small hotel miles away, then house moving plans...we moved within 2 months of each other, and are now 1/2 a mile apart. The funny thing is, although I found it a bit disturbing and frustrating at the time to say the least - this happened over a period of a couple of years and we both moved 3 years ago - we now get on well and meet for lunch/coffee once a month. Occasionally the children play together, but are at different schools ,so not often. Although my friend is a highly successful career woman in a tough profession, I think she must have emotional insecurities of a deep seated kind to have behaved as she did. Oh and she's coming to the end of renovating the house she and dh bought...I haven't seen her kitchen yet byt it's the same german company that mine's from !
4 years ago I broached this in a sideways manner, and her sideways response was to start on about how she felt her nanny was trying to emulate her...hmmm. I think she got the hint, sort of, but she just can't help herself.
Itried everything, from denigrating the choices I'd made "Oh I wish we'd not decided on xyz", to trying to be quiet about various plans, but it was the bit of distance that did it. I used to feel I almost hated her, but i tried to see it as an insecure person's sort of flattery, which made it a bit easier.
No quick solution to recommend I'm afraid, just try to stay relaxed.