Essential fatty acids (the omegas) provide core functions to the human body, but they are often times out of balance when on a standard diet. On keto, with a little bit of preparation, your omega fatty acids are easily manageable. If you want to know more about essential fatty acids, omegas, and how they interact with our body on a ketogenic diet, you can read more here >
The only way you can know how you respond to dairy is by slowly adding it to your meals. If you eat dairy and don’t notice any issues, you will probably be okay using dairy as a great source of fat. If however, you find that after eating yogurt or cheese you feel bloated, have cramps, get diarrhea or start vomiting, you will want to eliminate dairy until you figure out the cause. In some cases, people who were previously lactose intolerant have been able to add dairy into their diets after eliminating carbs, so you just never know. Food allergies are a tricky thing.
For those looking for something just a little closer to real sugar, you can use Xylitol. It cooks and tastes very similar to sugar, but it has a slight glycemic impact (13 vs. 100 for sugar). It is great, but please keep in mind that it is very toxic to animals and it will raise insulin levels slightly. These are the two most cited reasons for not using Xylitol.