Is Nicaragua dangerous?Yes! Just like anyplace else in this world where people are imperfect. Take the same precautions here as you would if visiting any other big city in the country of your birth.
Do they have internet and phones?Yes they do. That is how I'm able to stay in such constant contact with you. No we're not on the same network provider but the services are available here.
Do the stray dogs on the street bite?No. I can say for certain that they don't bite because they won't get anywhere near you. They have a morbid fear of man for good reason. They won't bother you even if they're travelling in packs. The dogs you should look out for are the ones that have no fear because they were raised by humans who don't know the first thing about training a dog. These beasties usually have already bitten their masters so what's one more bite to them?
Can I drink the water?No. Don't risk it. Especially, if you're just coming for a visit. There's no need to get yourself sick when you can prevent it.
How do people get around?There is plenty of public transportation to get you where you need to go. Besides all that renting a car here is about as easy as any place. There are at least two options if you're coming to Granada: Budget Rental