[Treadmill vs Outside]

I prefer to run on the road.  I get way to bored running on a treadmill.  My boredom gets worse the longer the run. 

[Not running 10min miles]

Don't worry about pace.  I agree with your plan.  At the end of the program, just increase your runtime by 1 minute each run until you get the full 5K.  Good luck!

[Can't seem to get past week 5 day 1]

My recommendation.  If you can't seem to get over the time hump, spending a couple weeks at the plan for week 4.  Instead, try increasing your pace gradually.  After a couple weeks, go back and try week 5 at your old pace.  Your body will appreciate the slower pace and the extra time should be easier.

 

I started C25K back in 2012 and in about 8-9 months I was able to run a full 1/2 marathon without walking.  I have not ran much now for the past 3 years and I am about to start the C210K today.  I have tried to start running again the past few years but can't past the soreness.  I am hoping starting from the basics will build me back into the swing of things.  Wish me luck!

[Life after 10k trainer]

I recommend only running it once per week.  Drop down to 50% on Day one, 70% on day two, then 100% full 10K on day three.  Repeat until 10k race. 

 

Once you get done with the 10k, time to start training for that half marathon. 

[Do you run heel striking first or ball of foot?]

I agree with their comment.  Just make sure you are not running flat footed (stomping).  It should be a rolling glide as you do make contact with your heal first but before you get full contact you should already be on the flat of your foot.  Sprinting is different, you want to sprint on the ball of your foot.