I also remember a guy who tried to say no by crossing his hands over his plate and getting a load of chickpeas dumped all over his hands!
Nice. Was the place catered? Because I’m sure it’s different if it’s family and friends serving as opposed to the caterers, who don’t care.
Caterers. They were in automatic mode. Step, dump, step, dump, step, dump … aaaahhhhh! … oops, sorry.
Not good to laugh, but it is kind of funny. 
At least in Hyderabad, I was advised that servers will keep putting food on your plate if it is empty. If you want them to stop, you have to leave a little bit on your plate. It runs counter to my Depression-era grandparents’ admonishments to eat everything on my plate but, hey, when in Rome…
Yeah, that is the culture over there. So it looks like you literally can’t eat one…more…bite.
Hope you are still following this thread…Just remembered a couple of things to be aware of while eating a South Indian meal on a banana leaf.
Don’t start eating the food as soon as they start serving. There is a very specific order to the food being served and there is a certain point at which you can start eating. More food will come at regular intervals - again in specific courses. I have actually done the serving many times when I was quite young - and got yelled at a few times for taking an item out of order.
The second rice course will be served with “rasam” - a very watery but fiery soup, to be mixed with the rice and eaten with the array of veggies that would have been served earlier and/or the crispy papad. Now, the more experienced will ask for the rasam to be served on the small mound of rice on the leaf…but you should ask for it to be served in a small glass. That thing will run like crazy and you might mess up your clothes. Also ask for the “payasam” (rice pudding) to be served similarly in a glass.
Also, be prepared for some super loud slurping from those around you eating with their fingers.
Wow, lots of India-themed threads I can contribute to today!
This is good advice above. Don’t start eating until people around you do (which will be after you get served some white rice and rasam or sambhar) and pay attention to the order in which they start out. After the first two or three things, it’s a free-for all. Also, I don’t agree that you have to leave something on your plate (apart from the salt and pickle, which I almost always leave, because there’s too much of both) but do be prepared to refuse something by placing your hand over your leaf well in advance. Just saying no will probably not work.
Also, when dealing with rasam and rice, think of it as an industrial irrigation project. Gotta build dykes and ponds to keep the flooding under control. 
Drastic action might include lifting the side of the leaf to prevent accidents. This is my approach, and it tends to work. Now I’m getting all hungry thinking about wedding food. Mmmmm.
I think you both look very comfortable in your Indian clothes, and they would certainly be very appropriate for a wedding. Go for it!