1. A ward can be placed on a threshold or a doorway or an intersection. That's it - it's not mobile. You could create a magic item with a ward on it and carry it around with you. Then, when you need it, activate it and it would be automatically cast on a threshold/intersection/doorway. At that point it would be immobile. You need to use the enchanted item rules for that, though.
2. depends. I 'quick' ritual is equal to your Lore. You could have an aspect "aware" that lasts a couple of scenes and you can tag it once for free. You can't put a block on yourself that's mobile, though, since that's a ward. The aspect could be tagged to help you dodge, though.
If you have time, you can stack as many aspects as you want. GM will have to decide how to balance it. How powerful? see #3
3. Every ritual requires a link. If the Evil Wizard has no material link to the target then they cannot affect you with a spell. Period. Players should be careful not to leave things lying around when storming evil necromancer's strongholds.
A ward of 9999? Same as powerful buffs. Many strong and powerful creatures and wizards will get alerted to that kind of power being drawn. Frogs start raining from the sky, bizzarre electrical blackouts, Weird visions in people's dreams, strange voices randomly coming out of the radio signals. When that happens, someone will start looking for you....
4. Chicken wings and beer