Hi there
Congrats on the birth of Archie!
I was in pretty much your position with my first 3 years ago, (lawyer on mat leave ) with some other established networks noticing all the mums with babies on the street! I was prob a bit hungrier for some local company as my mother's group took a long time to establish and also as my son got older excursions in the car became harder. Also as winter set in (he was born in August) I found it more of a pain to throw him in the car and do things.
I approached all of the neighbours separately and suggested catch ups to get to know them singularly and then as it turned out had a few catch ups also as a larger group.
It turned out I get on really well with one neighbour in particular and we catch up all the time during the week, most importantly for Friday night drinks on the deck in summer , and have looked after one and other's kids in emergencies which has been super handy.
The other I discovered after some time that I did not share too many values with overall and things have pettered out, which has been fine, we say hello and again in emergencies I have still looked after her kids and lent her the phone when she locked her kids inside whilst putting out the washing. We talk if one walks past the other on the street etc and have recent chats about kinder etc but thats it.
I think because I was not too overzealous at the time I had not invested too much time so not too much was lost if you know what I mean.
Looking back those friendships were really important at the time I was at home too.
My inclination would be to initially attempt a relationship with those who are newer to the area, if you can't invite them to your friend's party, even a note in the letterbox suggesting an afternoon tea at a local cafe or at your place if you feel comfortable would be well received.
I wouldn't necessarily write off the lady you share a wall with, we all know how we change after kids and she might welcome the invitation!
If you are all there for the long haul it is feasible your kids might be in the same class at school and at kinder!
Good luck!
Cheerio Belinda!