What exactly is essence

I've never drunk it (can't stand coffee myself), but the general theory is:

1. A wet ferment. Some coffee producers have attempted to duplicate some of the processes with enzymes, as you've mentioned.
2. More likely to be picked closer to peak ripeness. The animals have the advantage that they're picking berries to eat, and will pass over unripe ones to eat later -- unlike human processing which might just look to strip the whole bush.

In talking to one of my co-workers (also not a coffee drinker), and she said that she's had coffee right after it's been processed, and it was dramatically different from the stuff that was available in Europe or North America ... which leads me think that freshness might be a more important quality than some of the other aspects of the highly expensive coffee. (unless you're talking about psychological effects)

Practices will differ with country (or community in some cases) of origin. A country where few dairy products are commonly consumed or produced, or where a significant amount of the population is not dairy tolerant (parts of asia) or where religious codex exists about dairy use (eg jewish communities) is likely to have different practices from scandinavian countries that lead the world in per-capita dairy consumption.

Equally, the country where the product is marketed/consumed is important, especially when it comes to what has to be declared on the label, with which tolerance levels, by whom. Also try to take advantage of multi-language, multi-market label text - sometimes important hints are found only in foreign language versions of ingredient lists or allergy advice (ever noticed that they sometimes differ - where it is unlikely that two different products are described)....