MODAL VERB

Hi everybody,

I would like to ask about modal verbs especially about "should" and "would". I found that sometimes, I can use "should" and "would" to make a prediction, but sometimes, It is not correct to use them in predictions. Please take a look at my examples below:

I have 2 matters to ask as below:

*1ST MATTER: "SHOULD" VS "WOULD" FOR PREDICTION.

A friend of mine invite me to have dinner to his place and I ask him:
Me: What would you like me to bring?
My friend: Wine (should)/ (would)/ (will) be perfect.

Here is my opinions and what I learned from native speakers:

1. Should - > My friend know that that it will be perfect but he not sure 100%

2. Would - > The degree of certainty is higher than "should".

3. Will - > the degree of certainty is the same as "would", but "would" sounds more polite.

Are my opinions above correct?

Me: I know that mom don't like me buying these shoes. But I like them a lot. What If I buy it?
My sister: Then mom (should)/ (would)/ (will) scold you.

Similarly, can I use "should" with the same meaning as the first situation?

1. Should - > My sister know that that my mother will scold, but she is not sure 100%, she think my mother is likely to do so if I buy those shoes.

2. Would - > The degree of certainty is higher than "should".

3. Will - > the degree of certainty is the same as "would", but "would" sounds more polite.

*2ND MATTER: "WILL HAVE + PP" and " WILL HAVE +V_ING" and "WILL BE +V_ING"

My grammar book writes like this:

Future continuous, future perfect and future perfect continuous can also be used to say what we believe or image is happening around now.

Example:

1. We could ask to borrow Jim's car. He won't be using it today- he went to work by bike.

- >what is the difference if I use another modal verbs, and the most things I confused is about "should" and "would":

• ...He won't be using it today...
  -> I firmly believe so.
  
  
• ...He might not be using it today......
  ->I believe so, but I am not sure 100%
  
  
• ...He couldn't be using it today...
  - > It is possible that he won't be using.
  
  
• ...He shouldn't be using it today...
  - >Similar to wine example, I can use "shouldn't" to make a prediction (wine should be perfect) , so can I use "shouldn't" here to make a prediction as well ?
  
  
• ...He wouldn't be using it today...
  -> Similar to wine example, I can use "would" to make a prediction (wine would be perfect) , so can I use "would" here to make a prediction as well ?

The other example from that book:

2.Most people will have forgotten the fire by now.

- > will/could/might/should/would have forgotten ...

3.Tennis fans will have been queuing at Wimbledon all day to buy tickets.

-> will/could/might/should/would have been queuing...