Recommendation for old flat roof

Hi Leo:

Please DO NOT use my name or print this question, as I do not want to expose my HOA.

I’m not seeing where to send pics, so here’s a description: 37 year old original flat roof in sunny S. California.

1. 2 large areas of ponding with cracks (located in 1/3 of the roof) due to inadequate sloping.
2. 1 leak in 2016 in the ponding area.
3. 2009: silver coating painted on roof.
4. several patches have been done in the ponding area, along with caulking and black tar to cover cracks.
5. recent notice of "ladder like" appearance in ponding area, as well as "spongy/soft" areas when you walk on the roof.
6. cracks and holes in various areas (mostly around the standpipes, railing and water spotted areas).
7. There are 3 "house-like 8x10x8" structures on the roof <— should the base and top be checked?

8. There are 2 pieces of decaying wood that are attached to a wall that is built out of the roof (@ front of the building).

9. Would like to get your specific recommendations for BEST fix for the roof, specifically the ponding areas (will it need to be built up in the center vs. one estimator said 2 layers of rubber would completely take care of the problem) + type of material to be used. How soon do you recommend this be done? How much do you think this fix should cost?
10. Based on the condition of the roof, do you think we can get away with 1 more rainy season (El Nina-lighter rainfall) by patching the 2 ponding areas? The reason I ask is because of the costs involved in a roof replacement.
11. What should a "proper" job proposal entail, and do you recommend calling references from 5 years ago?
12. Should I choose a roofing company instead of general contractor to get this particular job done?

    Thank you for the opportunity to have my questions answered!