replacing an infinitive phrase that modifies a noun

Question

Here are some sentences where infinitives modify a noun. depending on the feature of a noun, whether it's a person or class or something, the way I should interpret the role of the infinitive is different. So I've made my own interpretation of this by writing sentences that mean the same that the original one does. Am I right to do this? The reason I do this is all for the sake of me fully understanding how to use "infinitive".

1. If you need anyone to talk with about this matter, feel free to call me anytime.

   =If you need anyone that you can talk with about this matter, feel free to call me anytime.

2. I'm currently participating in a class to practice English by speaking only in it.

   =I'm currently participating in a class in which to practice English by speaking only in it.

   =I'm currently participating in a class that is intended or designed for people to practice English by speaking only in it.

3. When you think you're ready, gather up some people to listen to your speech

   =When you think you're ready, gather up some people who is willing to listen to your speech

   =When you think you're ready, gather up some people who has an willingness to listen to your speech

4. w and b are parameters to be solved.

   = w and b are parameters that is to be solved.

   = w and b are parameters that has to to be solved.

Answer 1

As usual, your thinking is correct in these transformations. The revised examples carry the same meaning as the originals with infinitive. However, there are some unrelated problems:

In #2, you need to repeat the word "English", or "class", to avoid awkwardness/ambiguity, because as you have put the sentence,
- . . . class..,to practice English by speaking only in it

"it" can refer back to "class" or to "English". So, try this:

• . . . class to practice English by speaking only in English.

Or this:

• . . . class to practice English by speaking only English in class.

As for #3 and #4, you have missed the agreement in number:

• ...people who are willing... , ..,people who have a willingness

• parameters that are to be solved..., parameters that have to be solved