> I need only rhythm patterns shown, without pitches an lines, just bars and
rhythmic values.

Just use the instrument called "no instrument bar rests shown". This uses a
staff with no lines on it. Use a low pitch which is within the range of a
treble clef (F4, for example). The notes will appear with stems pointing up
and rests will also be shown.

> Another problem is that I need to show notes without stems. Is that
possible?

I don't know if you can turn off the stems. There are options relating to
them in the edit staff dialog, which is opened from the edit instrument
dialog, but I don't know if these are of any use in this case.

Another way might be to use the symbols on the note heads row of the symbol
dialog. The note head is the round part of the note. You'll have to position
these manually on the staff and this is not easy for us. I'm not sure
whether these symbols are positioned relative to the centre of the symbol or
the bottom of the symbol , but if you select the symbol and use Ctrl+UpArrow
and Ctrl+DownArrow, you can move the symbol up a line at a time. Using
UpArrow and DownArrow will move the symbol up or down by 1/32 of the space
between the lines. As you can see, not easy for us.

> Another one: In the ward method pitches are shown as Do Re Mi Fa Sol La Ti
represented by the numbers 1-7. Is there a way to show just numbers in a
score instead of the note heads and stems? And, if all comes together, can I
also combine the stems with numbers instead of note heads?

This is really not easy. You could use symbols for the stems and text for
the numbers but it will be very difficult to position everything correctly.
The "best" way would be for someone to design a new music font for you which
Sibelius could then use to draw the notes. However, this requires advanced
skills. If this kind of thing is very important to you, spend some time
reading chapter 7 in the Sibelius reference. This gives you information on
how to make these kinds of heavy modifications.