Surprise Shower Invites

Please help! I am fully aware that one must not invite anyone to any showers if these people are not also invited to the wedding. This makes perfect sense to me. My aunt offered to host a couples shower for my me and my fiancé. I thought that a smaller family gathering to celebrate the upcoming wedding and spend time with family that I don’t see often (due to living in different cities) would be lovely. However, my fiancé and I have been living together for a couple of years and we have our household set up. We didn’t want there to be any expectation to bring gifts, so we asked if it could be called a tea instead, which my aunt understood completely. They suggested adding a note that a monetary contribution was optional on the invite, but we didn’t feel comfortable asking for or even suggesting people bring cash, so we asked for that to be removed. When it was pointed out that in this circle gifts at any pre wedding event are expected, I suggested that we ask guests to bring a written family recipe to share with us. My cousin suggested explicitly stating that we don’t want gifts on the invitation but I have read that it’s not polite to allude to gifts at all on an invitation, so I thought the recipe could be a good way for people to feel like they’re contributing something personal but without requiring them to buy anything. Anyways, my stepmom helped my aunt with planning the tea, and I am so grateful for their generosity and all the time they put into it. However, when we arrived at the event, I saw that my stepmom had invited seven members of her family without my knowledge. This would be fine, except that these people are not invited to the wedding (my stepmom knows this) and our current guest list is at capacity for our venue and budget. They all brought gifts. I will of course be sending thank you notes to everyone who attended the tea but I can’t stop worrying about the guests who were invited to the shower but not the wedding. I don’t know what to do and I feel like I’ve accidentally been horrendously rude but I don’t know how to address it.