Torchic, treeko, and mudkip
You can't. Palkia is from Pokemon Pearl(Generation 4) and Pokemon Ruby is a Generation 3 game. You can transfer Pokemon from Ruby to Pearl/Diamond through the Pal Park, though.
No, Parchirisu is a Pokemon that was introduced in Generation 4. It is not available in Pokemon Ruby (Generation 3)
a tepig\
turtwig,chimchar,and piplup
You have to trade them from other games.
In Pokemon Ruby there is the 3 regis, rayquaza, latios, groudon, deoxys, and jirachi. So there are 8 legendarys.
Palkia is not available in Ruby as it belongs to Generation 4 (Ruby is Generation 3)
torchic mudkip and treeco
Somewhere. =3
Cyndiquil, Chikorita, and Totidile.
Pokemon ruby's version IS Pokemon ruby.
Pokemon Ruby has Pokemon that Pokemon Sapphire does not and Pokemon Sapphire has Pokemon that Pokemon Ruby does not.