It seems there are also special holiday prices and weekend rates, so it's at least twice as expensive for now. The information is probably still preliminary, and it might be possible to negotiate a bulk discount that's not based on the standard price list. That's why I asked Alexxl to try and consolidate everything, including the cost of three meals a day, the rental of the hall (which is also listed at 1200 rubles per hour). Then we can compare it with the prices in Yekaterinburg.
Regarding accommodation and its prices, to give a more or less adequate answer, we need to understand for each individual person what type of room they plan to book and for how many days they plan to stay (i.e., the exact arrival and departure dates). As you correctly noted above, the price varies depending on the days of the stay.
Regarding the conference hall, the price will naturally be lower than the one listed in the price list.
Meals: breakfast is included in the room rate, and it is possible to order set lunches and dinners (the cost can be tailored to our needs, depending on our budget).
I will probably post an approximate price range for May, taking into account discounts, on Saturday evening, as I have a meeting scheduled with the owner of the property. By that time, we need to know the dates of our event.
P.S. I would recommend booking cottages, as they are more affordable and much more convenient; essentially, you get your own separate house!