They can settle in a double room, that is, with two separate beds. Since you do not put a stamp on marriage in the passport that you present to the hotel administrator upon check-in, you can inform that you are a married couple. Different surnames are allowed at the time of marriage, a minor girl can be married to the laws of Russia from the age of 16.

Each hotel, depending on its rating on the international list, has its own requirements regarding the population of tourists in the rooms. You can clarify such nuances by choosing a hotel through a travel agency.