Will there be an altar on the map?

We'll find out tomorrow.

What does 5 Creature Dwellings have to do with it?

I think it's no longer relevant, as the Monster Week will probably be banned.

And also, should I save the game every day, i.e., should I save all 27 saves on the disk?

According to the tournament rules, if there are any questions for you, the host may require you to provide saves for the end of each day (or for any of the days - as needed)... Whether to save them or not is up to you. This is one of the main rules for offline tournaments, but it is usually not explicitly stated, based on the assumption that all players understand this... You won't believe it, but on HP, players sometimes have 1500 saves per tournament. But not because someone will demand them, but simply having the ability to replay a turn starting from any moment is an advantage, from the point of view of saving time... :)

Although, it might make sense to explicitly state this in the regulations - mandatory storage of daily saves for a certain period of time, starting from the announcement of the tournament results? So that in case of controversial questions, the player cannot refer to the absence of saves... This is a perfectly normal practice.