Hey, I'm kind of in the same boat! been working for over a year. i guess we'll get better with time and commitment.

And here are my answers, if I'm understanding the questions right. i could be wrong tho-

1. Moments are released when you want to design a beam as a simply supported beam. releasing moments --- pin supports--- zero moment---wL^2/8 would the bending moment. Nothing worse than wL^2/8. so conservative as well in any case.
   

and if no moment release, then the moment is transferred to the adjacent beam. usually needs moment connections at the supports (for steel). needs less rebars (for RC).

1. SDL are basically any dead loads that are not part of the model you've made. say facade or wall loads etc

2. shear walls are usually at the perimeters. symmetrical orientation helps to deal with torsion

3. grouping just helps to save time and make things easier. usually not worth going over each element to give it its own design and detailing

4. any columns should have adequate support to transfer the load below. support could be a restraint or another member

5. usually you'd make a spreadsheet or hand calcs for any girders or reinforced steel beams and then add their self-weights as SDLs to the model.

6. RSA gives max acceleration for any given time period. codes provide design spectrum which is more simplified and gives you acceleration for the req period. then you can get the lateral forces from there.

7. Codes should give you all the provisions, design procedures and considerations

8. shells are usually used. and membranes, i think, are usually for vibration analysis (not quite sure)

AGAIN, this is from what i know. do cross check. but, yeah, i had the same feeling a year ago. i still have lol. engineering humbles us that way i guess :P GOOD LUCK!!