Dropping food on the floor - personally I chose to ignore any food that reached the floor, responding and picking up during the meal (IMO) can lead to more dropping as LO learns the reaction and to play with you as you keep returning the food. This learned behaviour (dropping to get back) is very similar to learning to roll or throw a ball with a parent or play mate (giving to receive) but one of them drives us crazy and dirties the floor whilst the other thrills us and makes us smile.
Mine rarely managed to actually get much food to the floor, I offered very few pieces if he was in a dropping phase (moved the plate out of reach and put only one or two bits in front of him) and reacted quickly to stop his hand from dropping it if I saw it about to happen and just popped it back on his plate/tray, or even better I got the plate under the food item as he dropped it and said 'tidy up please. Thank you' and encouraged him to tidy all his bits onto a plate or bowl at the end of each meal.
Yoghurt - is there a reason she needs to have yoghurt if she doesn't like it? In general we keep offering foods so that LO becomes familiar with it and eventually tries a taste, but you can't force them to eat it and I found some dislikes are long lasting. Mine still doesn't like cauliflower and broccoli I see them as true dislikes because he has been offered them so many times and otherwise eats well, I still offer time to time but always make sure his meal has plenty of things he does like to provide a balanced diet.