Yes there is.
Yes it's semiformal.
Only if it was indicated on your invitation and you let me know you are bringing someone.
No children allowed.
Please try to arrive 15 minutes before ceremony is to commence.
Even though the invitation says to RSVP by 9/16, we would greatly appreciate no later than 9/14.
No I am not registered.
Most probably there will be. Even though it is an outdoor event...the venue may require proof of vaccination if the guests need to go inside to use restrooms.