With respect, OP, you're going to need to be way more flexible in your communication styles if you are going to live and make friends outside your home culture. Not everyone is going to understand things you think are obvious.
The kind of indirectness or 'subtlety' you seem to imagine you both view as 'necessary politeness' clearly isn't working here, if you continually fail to communicate what you actually want and don't want to her.
You think it's clear an excuse means 'no', but she clearly didn't get that memo. (And Latin American and Eastern European cultures are very different, and I imagine that they use indirectness differently, as even two neighbouring countries like England and Ireland use indirectness very differently -- an English friend moved to Ireland a few years ago, and despite thinking she was a comparatively 'politely indirect' person in her home culture, she's far too direct for many of the Irish circles she's moving in.)
Either way, your 'subtlety' isn't working. You are not communicating, and you are blaming her for not understanding what you mean, but have not said, the way you think she should understand.
You are currently blaming her for not understanding that your 'soft negatives' about your birthday in fact meant 'No'.
You're blaming her, or possibly her husband, for your husband not being clear about having already paid your part of the bill.
You're blaming her for not understanding that when you posted about sharing workspace to an MeetUp group you know she's a member of, that your open question about sharing workspace wasn't intended for her, and you actively don't want to share a workspace with her. Although she's a member of the group your posted on.
You're also blaming these friends for being 'too direct' in criticising other friends of yours, despite the fact that it turned out those other friends (whom you are not blaming) didn't like the friends you are posting about either. So both sets of friends dislike one another, but you're only blaming the ones who said it within a few months rather than the ones who waited two years to say so -- ie, in this case, you're criticising the friends for being too direct.
And honestly, OP, wouldn't you rather know almost immediately that two sets of friends don't get on, rather than spend two full years unknowingly inviting them to things together, only to discover they've hated every second?
I'd certainly rather know, so as not to inflict unnecessary irritation on anyone.