Air is fine. You should only need about 80psi to do the job and that can be regulated by the leak down tester or other setup you use. DO NOT use your direct full air from the compressor. You need to regulate it, just like when you paint. Too much air in the cylinder will allow the engine to rotate if it's not exactly on cylinder TDC so using less is better. Each cylinder will have to be on it's TDC to do this. Once you get it on a couple it'll become easier. Also, once the cams are out, the valves will be closed and you don't need to worry too much about TDC on each cylinder but DO have to make sure there's enough air in the cylinders to keep the valves closed when removing the keepers and springs.
Changing springs at the same time is easy because you have to remove them for the seals anyway. This is the time to do it. I'm a Comp or Crane guy myself, but Motorcraft will be fine if you're staying stock.
Camshaft timing is critical but not hard. The key is knowing where #1 TDC is and lining everything back up when you go back to install them. There are a few good videos on how to degree a cam (you shouldn't have to go that far
View: https://www.youtube.com/watch?v=jFOZhV1tFyE
). You'll need to know how to get the crank at #1 and install each cam accordingly. Crank and cam gears have marks and the chains do to (usually a dot/paint or other mark) to index them. However, you may not see the chain mark due to mileage. You can make your own simple marks on the chain for reference, but if the engine has high mileage, I'd replace them with new chains and guides.
The biggest thing I'd say is be patient. If this is your first, take the time to be thorough. Keep ALL cam caps and parts in order. DO NOT mix them up. Set an area so you can lay out the parts as you take them off and put them back in the same place. You will be working under the hood and running into objects that may get in your way a bit, but it's not impossible to do. If you're really unsure, removing the heads from the engine would be less stress, but a lot more work, and, you'll still have to set the timing chains correctly. It's all up to you.