Let's be frank - it is entirely your choice how much of the traditional 'to do' list you follow in regards to planning your wedding. It is your decision how many rules you choose to follow and aside from the legalities there really are no essentials.
However, if you are still uneasy about bending the rules, here are some very easy ways to simplify you and your partners lives pre-wedding.
1. Seat Allocations.
There is no rule to say that your guests need an allocated seat - after all they could just sit wherever they would like (wild, I know.) However, if going completely rogue is giving you anxiety - there's absolutely nothing wrong with allocating tables instead of seats. It's so much easier and less stressful. Plus you can also eliminate name cards. (If you do have guests that need a specific seat due to health issues for example, you can still allow for this.)
2. Wedding Favours.
Most guests probably wouldn't be the slightest bit worried if you don't do wedding favours (I dare say they would be more worried if there was nothing to eat or drink!) However, if you're keen to give something but don't like the idea of adding an extra 120 pieces of plastic to landfill, ask your guests to take home your floral table decorations or choose an edible favour instead.
These really are unnecessary. Most guests have a fair idea of what to expect from a wedding and will probably cope without having a programme detailing every half hour of events. If you have elderly or disabled guests, who would find comfort in knowing the events of the day beforehand, it is nice to touch base with them in person a few days before the wedding.
4. Choreographed Anything. If you've been going to dance class for the last 25 weeks so you can bust out a flash mob style dance with your bridal party - with intention to go viral -obviously disregard this. But if the whole idea of spending hours rehearsing for your own wedding doesn't spark joy, leave it out! Again ask yourself - are you doing it because it's meaningful to you and your partner, or because you feel it's the done thing?
We aren't saying you should send out a facebook invite (unless that is what you want to do.) However there are invites and there are invites. There is nothing wrong with leaving out at least a few of the 17 additional pieces of paper that seem to comprise a wedding invitation. Ask yourself whether your guests really need a map, a list of local activities and a timeline for your day. If they don't, simply leave them out.
There are plenty more ways to simplify your wedding and if you are in doubt about any particular element when it comes to your wedding, there is absolutely NOTHING wrong with leaving it out. Always come back to what is meaningful rather than what is expected.