have strong Pokemon
no
snowpoint city, the battle zone (you can battle him on weekends) and stark mountain.
On route 119, your rival will give it to you after you beat them in a battle.
after you beat your rival at battle tower he will reappear every so often
Your Rival is in the Pokemon league on Mondays and Wednesday. On Tuesday,Thursday and Fridays, your rival is in the Dragon's Den training
His Eevee will become Jolteon if you beat him at Professor Oak's Lab and at the optional battle at Route 22, provided you beat him just at Professor Oak's Lab then his Eevee will become a Flareon and provided your Rival beats you at the Lab and the optional battle on Route 22 or you lose at the lab and you skip the Route 22 battle then your Rival's Eevee will become a Vaporeon.
At mt.moon you can battle your rival and then once you beat him go to dragons den and you will battle with him against Clair and lance and be ready for the battle your life
You cannot progress through the game or get to other regions without beating your rival in the Pokemon game. It is specifically designed so you have to battle and beat your rival.
You can battle your rival at the Pokemon league on mondays and wednesdays
Yes there is your rival if you pick Treecko or at battle hill after you beat the Elite 4
you must beat the seventh gym leader and then when you walk out you will battle your rival. after you battle your rival you will then be able to find dragonairs in tall grass
When you go to Stark Mountain you will meet your rival (you won't battle him/her). After that you will be able to face him at the Fight Area on the weekend(Not on Friday).