There is a high likelihood that you will NOT be able to get tickets for any of the trains that you mention. I am not sure that tickets are sold for the #10 to disembark in Sverdlovsk. This is a very popular long distance train and is usually reserved for much longer distance travel.
In addition all these trains are VERY popular and likely to book up way in advance and you are not boarding at the point of origination. Tickets for these trains may not be available until 72 hours prior to departure when it is better known how many berths will be available. Also tickets will more likely be available at the station of departure than elsewhere.
For the #6 train, this is an international train. There may be a car attached to disembark allow passengers to within Russia but I would not guarantee it.
The #24 train from UB to Beijing will operation only on Thursdays. You won't find it on the poezda.net site because it does not originate in Russia but in Mongolia. There is NO Mongolian train website so you will just have to take my word that the train exists and operates on this day.
Bottom line, if you are planning to travel independently then you cannot be guaranteed that you will be able to take any of these trains on the days that you plan. I am not sure that a travel agency will be able to do this program either.
There are NO hostels in Novosibirsk and the hotels there are VERY expensive. Even homestays are expensive. In addition unless you are interested in Soviet architecture, the ballet or opera or need a fix at an Irish pub in the middle of Russia, I would not recommend stopping there.
Spend more time in Krasnoyarsk. Get out of town and visit Stolbi, Dvinogorsk dam, the ethnography museum, etc. Contact Anatoliy Brewhanov, the SibTourGuide for some assistance and ideas of what to do.
Ruth