For morale you roll your leadership, and one model runs if it fails. After that each 1 makes you remove another model. 2s if you're under half strength. You could potentially lose an entire unit.

The falcon hull costs 115, the weapon an additional 10-20 depending on what you pick. Think of it as saving a step. So if you want to upgrade to a AML, which costs 20, you just add it to the base cost. You don't have to subtract the 10 from the weapon you're replacing first, then add the new one. Points always calculate as model(115) + weapon (10-20) even on smaller models, it's just that their basic weapons are frequently free.

Look out sir has gone through a few changes. Atm any vehicle or monster can protect a character, unless that vehicle or monster is itself a character. At 10+ wounds a vehicle/monster that is a character can no longer benefit from Look Out Sir itself, but can protect another, smaller character.

I haven't messed with the app, but there are two ways to get codex access, as far as I know. Paying for a subscription gets you all the old codices, until the 9th Ed codex for that particular faction is released. When 9th codecies release they will have a code that unlocks them in the app. Im not sure how you'd go about getting the 8th Ed codex in the app without a subscription, but it's probably not worth it. While they take some time to update, wahapedia and battlescribe do a good enough job of keeping updated rules for each faction easily accessible for free. Between the two you shouldn't have any problem while waiting for a new codex to release.