Parce que Koutchma se rend à Moscou, certains députés du parlement ont demandé au Ministère de la Défense de faire des exercices de défense anti-aérienne.
nota : The Ukrainian system being unicameral, when you say "députés" they are, ipso-facto, "du parlement". So you can omit it.
1- When telling someone what you do, you say : "Je suis ingénieur".
But when adressing him, you say : Monsieur l'ingénieur. ( or Monsieur le professeur).
Adressing him "Monsieur ingénieur" doesn't make sense.
About the rules, I'll try to put it straight later.
2- "informations" are countable. You can have one or more informations about something. Hence you can say : j'ai trois informations sur cette affaire.
3- About accents : yes, there is a logic.
accent aigu :
é like in "café" (sound "eh" as in eheh!)
accent grave :
è like in "après" (sound "ai" as in air)
for other accents see this link :
Accents
Your example - demande, démanteler. This words are of different etymologies.
Demande - old french "de mande" on order(of someone with authority).
Démanteler - old french - préfixe dé : ôter + manteau.
You can not apply a logic of accent on words of different families.
4- Let's put order :
When you are on the way to a specific shop : Je vais à la station-service.
When talking about an event: Cela s'est passé à la station-service.
When you are there and you know it by being there before : Je suis à la station-service.(It implies the person you are talkink to also knows it).
When you are there but you dont know it : Je suis dans une station-service.