What engines can be installed under gogui? please give a link to them.
can any engine match be held under them?

does engines of go have any evaluation?

pachi: http://pachi.or.cz/
fuego: http://fuego.sourceforge.net/
gnugo: http://www.gnu.org/software/gnugo/

gogui can run a match of several games between a pair of programs, but not a complex tournament with more than two programs.

Evaluation is engine-specific. Monte Carlo programs usually offer win rates, whereas a classical program like GNU Go uses territory estimation.