We have a favourite spot for Wishes - call it our secret spot, but lately it's been pretty full. But it's out of the way and no one stands in front of us. There is a path on the right hand side of Main Street after you pass the ice cream shop past the water and before the popcorn cart that runs from Main St. to the Tomorrowland bridge. It's a perfect spot about halfway down - the fireworks are right there, the castle view is amazing, usually ducks entertain us while we wait and you can sit on the path and lean against the railings - and Tinkerbell flies almost right over you! We usually get a spot about 45 min. before Wishes if we can and send someone for snacks nearby. Not sure about Spectromagic, as you can't see it very good from there. We usually watch that in Frontierland where it's not so crowded and then try and make our way over to our Wishes spot, or we do them on separate nights.
As for exiting the park with small children, please heed my advice

Do not do the exit shuffle

You will not be happy, your children will not be happy! No matter how tired and miserable the kids may seem, everyone will be happier if you just wander around and kill time for at least 20 minutes or as long as you can stand it. You will be amazed at how much less stressful it is to just enjoy the nighttime lights and then wander out to the buses with full strides a bit later. Find a bench in Adventureland, or head to Tomorrowland and loop around behind the castle if they'll let you - visit some gift shops if the kids can handle it, or just sit and stare at the castle changing colours while you wait - it will be worth it. We did this with our friends this past August - they had a stroller and it would have been impossible to think of getting near the exit. We shuffled through the crowd across Main St. to Adventureland and just enjoyed all the empty space, let the kids run around and waited. After less than half an hour, out we went to our bus, waited about 10 minutes and actually got seats.
We do this at all the parks - the gift shops stay open about an hour afterwards, so don't feel you have to rush out with everyone else. Enjoy!