Inviting guests to wedding breakfast and evening, but not ceremony

Sounds perfectly fine. Have shot weddings just like it. Just explain to everyone the situ with the ceremony room numbers.

I am assuming that the ceremony and wedding breakfast are at the same venue.

It is unusual for a venue to have a big mis-match in the number allowed for a ceremony and the number for wedding breakfast.

Maybe look at live streaming the ceremony, my brother had to do that as Covid rules meat they could only have 10 people in the registry office for distancing as it was so small, but could then have 30 for the afterpart, it worked well as people still felt they were at the wedding. At the end of the day as long as it is what you want and you explain the situation no one should be offended. Maybe word it that you want an intimate ceremony of just immediate family but you would love for them to join you for your first meal as Mr & Mrs. the other option is to have a later ceremony at say 4pm and have the immediate people you said above and then have your evening start at 6pm for everyone else and this would also save costs hosting a meal and evening food, you could have one massive buffet at say 8pm, as your day guests would be able to have a later lunch before the ceremony so they would not need to eat till later.