Starting To Get Stressed

1. We had an unplugged ceremony, but allowed for people to take photos or videos at our reception. We had our officiant make an announcement for guests to please put their homes away. Hopefully your guests will respect your wishes, but unfortunately you can't control what they do or if they post on social media.
2. Again this isn't something you can control so try not to stress over it. Hopefully if someone is late they will quietly take a seat without interfering with the processional or ceremony.
3. Your bartenders should be able to tell if someone is too drunk and will cut them off. Also let's hope your guests are smart enough not to drink and drive.
4. No one did this at our wedding. But unfortunately this did happen at my brother's wedding. Luckily they had enough space for him to stay.

You're welcome I hope you have an amazing wedding

Try to take some time for self-care to relieve some of your stress in this last little while before the wedding. As far as your specific concerns:

1 - Ask your officiant to make an announcement. We didn't have anyone posting to social media, and though we had a couple people who took photos, they didn't get in the photographer's way.

2 - Try not to let this live in your head, people might be late (or right at the start) but people are unlikely to walk through the processional to their seats, they're more likely to find a place at the back and to the outside.

3 - Trust your bartenders to cut people off - that's why you hired them. If you're getting married in a more populated area, then people who are too drunk to drive will call for Uber or Lyft, or find a ride - most people know when they've surpassed their limits.

4 - You're probably not going to have this either, but if you have a DoC just mention this is a fear and they'll help take care of it.

Seriously though - take a bit of time, get your nails done, get a massage, have a glass of wine (or whatever makes you happy) and watch a movie - anything where you're not dealing with wedding in these next few days. It'll help a lot.