Hi JD! Congrats on a great purchase! Lots of good times ahead with your #3!
Don't feel overwhelmed, as we were all new to this at one point. Smoking in these types of smokers is definitely different from a lot of the "traditional" methods; they hold moisture much better, plus they take very little wood to get a great smoky flavor, and the meat isn't overwhelmed by the flavor of the "heat" (like charcoal). I find this allows us to focus on the prep and seasoning, and lets us make some really stellar Q (with a LOT less effort than the traditional smokers).
One thing I would recommend is to go over to the recipe section on this forum, find a recipe/method that looks good, and try to duplicate it as close as possible. We have many successful smokes there that are specific to our smokers. The "one size fits all" sites will get you confused with too many methods. Keep it simple.
To give you educated answers to your first question about the ribs, we need a little more info. I see Memphis dust and 5-hour no peek, but the following will help:
What kind of ribs?
What was your preparation (any binder, like yellow mustard? Did you remove the silver skin? Did you leave in the fridge overnight with the rub on them?)
Did you use a water pan?
Did you open the smoker door?
What kind of wood and how much?
The more details we have, the better we can help.
As for the "fall off the bone" tenderness, you just needed more time. The 5-hour mark is just a guideline, depending on your ribs. I usually do 3 racks of baby backs at a time (that's how they come from Sam's Club, which are really meaty ribs), and they usually take 5.5-5.75 hours. I start checking them at around 5 hours, then go another 20-minutes at a time until done. You can check them with a wooden toothpick; stick it in between the bones and feel the tenderness, then pull sideways to see if the meat pulls from the bone. This method works great. I have never smoked a rib that didn't leave a clean bone when done!
Moisture is key for meat like ribs, pork butts and briskets, but not necessary for whole chickens or turkey. They have a skin on them, so they just don't absorb the moist air. The preferred method for poultry is to brine them. Check out the brine and poultry boards for ideas. I have a couple on there that work well. For moisture on ribs and such, I use a disposable aluminum "mini loaf" pan from WalMart. They hold enough apple juice, have good surface area, and tuck in nicely on the floor of the smoker next to the smoke box. Don't put it on a shelf - put it on the bottom so it gets hot enough to boil.
In regards to your question about cooking chicken and ribs at the same time: It's always tough to smoke dissimilar meats at the same time, as they cook differently. A whole chicken will take around 4 hours to reach 165 internal temp, and the ribs will take longer. I cook these at different temps, too. Chicken gets 250 and ribs get 235. I know lots of folks do, but I never cook 2 totally different meats that require different methods at the same time. Just me, though. I would probably smoke the ribs first, wrap them in foil and place in the oven set to 140 to hold while the chicken smokes. Others that smoke these kinds of different meats at once (hopefully) will add their nickels-worth of advice.
Also, do you have a good remote thermometer to monitor internal temp? You'll need one for the chicken. Except for ribs and jerky, I always cook by internal temp, not time.
I know this is long, but we're here to help! Spend some time reading the posts in the recipes, and you'll learn how to make some great Lazy Q!