Check out this thread: https://www.homebrewtalk.com/f39/post-your-infection-71400/
Taste it. Any off flavors? Like sour, vinegar, farm animal, buttery....
So the 1098 is the whitbread dry strain. It is more attenuative than the 1338 so you'll likely get a drier beer in the end. Its a clean yeast, I just used it on a batch of English brown myself, it takes a little longer to clear than the 1338. With the caramel malt in your recipe you'll have...
Rebel Brewer has some: http://www.rebelbrewer.com/shoppingcart/products/Citra-Hops-%28US%29-%252d-1oz.-Pellets.html
This year's harvest will be packaged up and shipping out near the end of September.
I carb my american styles at 7psi for a week. What you can do is take it off the gas, bring it to room temp and bleed the pressure relief as often as you can for a few days. Then use this chart to re-carb: http://www.kegerators.com/carbonation-table.php
That's fine. You'll get plenty of enzyme activity at those temps. Did you rinse with warmer water? If not you may have left some sugars behind (which would account for missing the target OG). You won't get any problems from that mash, just a more fermentable wort.
Its tough to get an idea for alpha at home without just brewing a batch. What variety? Some keep better than others, I know cascades have a poor shelf-life.
The spices will have a 'cooked' flavor in the cookies and adding them to the boil would have aligned those flavors more closely. Not cooking them will give you a slight difference in spice character but I wouldn't say you messed anything up flavor wise.
I get the eggy/sulphur smell in my ciders too, not a problem, takes about 6 weeks before mine is cleaned up and tasty. It should fall clear when the yeast are finished up, unless you boiled your apple juice.
6 months is pretty old, quite a bit of the cells would have died off during that time. I say go ahead and pitch the starter. The few viable cells you originally pitched are probably working their ass off to get the population up, hence the lag.
Welcome man. Just a couple questions, may help us help you better.
What was your starting gravity?
What yeast did you use?
Is your cider clear or cloudy at the moment?
Any activity on top of your batch?
Can you descibe the smell? Sulfury/Rotten Egg? Alcoholic? Vinegar?
Recipe looks good to me, the low gravity will give you a quick turn around. I'd pitch that starter at high krausen to jump start your ferment. If you can hold the temp steady you should have no trouble getting to final gravity in 3-4 days. Be nice to allow the yeast some more time to clean up...