Putting a washing machine outside should really be a last resort. If you go that way make sure you have an outdoor GFI power socket to use. Electrical work should have a permit. Consider if there is anywhere you could add a bump-out closet with a door opening into the house for your washer/dryer. Bump outs for fireplaces or bay windows can often extend into side yard setbacks. Check with your building/planning department.
A sun tunnel is fairly minor work. Be certain all flashing on the roof is water tight and meets code. A leak would cause almost endless headaches.
The labor cost for installing a window is very roughly equal to the cost of a high quality window of the desired size. So the total cost is very roughly twice the cost of a high quality window.
Depending on how old your brick fireplace is it could be more of a structural hazard than providing any support. It is very unlikely the city would require an engineer or architect. If your chimney is completely external to your house, the demolition cost shouldn't be very high but there will probably be over a ton of broken bricks to haul away.
Always ask yourself would you buy a house which had the the changes you are planning, done the way you are planning to do them? If the answer is probably not, then you will probably pay twice, once to do the changes, then a second time to do it right when you sell your house.
Call me. We can discuss rough estimates that I'd rather not put in writing for liability reasons... and I can refer you to some contractors that if you are still interested after I give you a "ballpark" sense of feasibility and cost.
Good luck with your projects!