Codes P0339, P2305, P0837, how to repair

Hello and thank you in advance for taking the time to read and respond.
My vehicle listed above Sport model is throwing these codes:

P0339 Crankshaft Position Sensor A Circuit Intermittent Stored
P2305 Ignition Coil B Secondary Circuit Confirmed
P0837 Four Wheel Drive Switch Circuit Range/Performance Stored

Tomorrow, I am going to pick up 6 new spark plugs. I intend to replace those and also do a little musical ignition coil (at the suggestion of Steve on here, thank you Steve) to see if my second cylinder ignition coil is causing problems.

I am going to purchase a crankshaft sensor but was wondering if you think that would fix anything. I am not sure if the spark plugs are also possibly affecting other electrical such as crankshaft, or if they are separate issues.

As far as P0837, what should I do? My Part time light is on almost all the time, and my car is always in 2Hi and I can't change it. So does that mean it's four wheel drive switch that needs replacing? Are transfer case switch and four wheel drive switch the same thing?

Also, a problem I haven't mentioned yet, I get no air blowing through unless it's on 4. I replaced the blower Motor resistor and that solved my problem for a month exactly. A month after I replaced the resistor, it stopped blowing on 1, 2, and 3 again. So does that mean my blower motor is always broken? Not just the resistor? Thank you, happy Halloween.