To what extent 'Reality' be included while writing 'Realistic' Fiction literature?

According to wiki,

Realistic fiction typically involves a story whose basic setting (time and location in the world) is real and whose events could feasibly happen in that real-world setting.

This is really ambiguous definition. I have few questions regarding the same:

1. Apart from basic time and location, what real entities are allowed during writing?


2. Considering the definition, can most of the written TV soaps be termed as "Realistic" fiction?


3. How should the tone of Narration be while writing Realistic fiction?

Answer

My experience is with novels, as opposed to screenwriting, but I can give a general answer about the genre.

1. 
   
   

   There is no inherent maximum or upper limit to amount or type of real entities that can be used within Realistic Fiction. For example, real-world companies, products, historical figures, etc. may exist in Realistic Fiction. However, for legal purposes, one should take care how any real-world persons, companies, or brands are portrayed.

   
   


2. 
   

   Yes, most. There have been some soaps/soap opera format shows that included some non-realistic or speculative elements, such as spirit possession, vampires, magic, etc.

   
   


3. 
   

   Tone and genre are not necessarily dependent on each other. A written work may be humorous or dramatic in tone, for example, and still be realistic.