Q: Why do editors change titles of posts? Can junior users have more control on approvals? I understand the need to edit for clarity in the contents of posts, but why do editors change the title? If there are errors, I can understand. However, my title reflects my thinking, not that of an "expert" on the topic. If I am searching for something, another non-expert might search or think in the same way.
My first two questions had their titles edited and approved by other editor-badged users. The new title does not reflect what I was asking (IMHO).
Can new or junior users have more approval control on those types of edits?

A: 
why do editors change the title?

To improve the clarity of posts.

The new title does not reflect what I was asking (IMHO).

You have two questions.  For one of them the only change to the title was to remove a tag from the title and apply the correct tags to the post.  The semantic title wasn't changed at all, so it still reflects what you're asking.
The other question's title has been changed a lot, and by numerous people (including several changes by yourself), so that's clearly the interesting case here.  Let's go through the changes one at a time:


*

*The fourth revision fixes a typo; this is clearly goodness.

*The fifth revision was made by you, so presumably you think it was good.

*The seventh revision adds the information that you're looking to specify the type of instance variables, where previously your title indicated that you were looking to specify types of parameters.  Given that the body of your question makes it clear you're looking to specify instance variables, not parameters, this seems to be moving in a good direction, but the new title is still confusing, and needs more work (fortunately it gets more work).

*The tenth revision was made by you, and is a significant rewrite in terms of phrasing.  Honestly, this is the first really good looking title I've seen for this post yet.  You're incorporating the fact that the previous revision indicated an ambiguity between parameters and instance variables, and now, instead of being ambiguous, you use both terms (correctly) and indicate what you want from each, and how they interact.  This is much better than all of the previous revisions, particularly those before the previous, as this really tells me what the question is asking.

*The eleventh revision makes two changes, it pluralized "variables", which is correct, although not really essential (knowing how to do it for one would tell you how to do it for multiple, but  you do have multiple, I'm ambivalent about this one).  Then it changes the second part from indicating that the parameters are strings to just not specifying a type.  This just looks wrong, because it's actually relevant to your question that the parameters are strings.

*The twelfth revision re-adds the fact that the parameters are strings, reversing the error made by the previous revision, as well as making a few more minor pluralization changes that look correct to me.

*The thirteenth revision re-applies the mistake made in the 11th revision, and is done by the same person that made the erroneous change the first time.

*The fourteenth revision rolls back to the twelfth, by the person that made the twelfth revision, and does so correctly to reverse the error that has been applied for the second time.

*The fifteenth and final (as of the time of this writing) revision was again by you, removing some redundant information from the title.


So.  Wow.  Lots going on there.  Key takeaways are that most of the revisions were beneficial (most of them only by a little bit though, although a few were significant improvements).  There were two bad edits that changed the meaning in ways that were incorrect, given the body of the question, but both were corrected within just a few minutes by other users.  Relevantly though, the title that we ended up with is great, and much better than where it started out as, and while a lot of the credit for this is yours, as you made a lot of the improvements, others did add significant and real value to the clarity of the title.
Of note, both of the bad edits were made by a user without full edit permissions, and thus had to have their edits reviewed by others first.  It's a shame that this person has earned 4 rep for suggesting the same bad edit twice, and having it approved, and later rolled back, both times, but at least the post was fixed right away.

Can new or junior users have more approval control on those types of edits?

You have basically as much control as you possibly could have.  If there is a pending edit from someone without full edit privileges, you can unilaterally approve or reject the edit, and you can unilaterally reverse the community's decision on the review if you don't like their decision (as long as there haven't been more edits since).  You can also always roll back any edit (even from someone with full edit privileges) or always make further changes if you only like some of what was changed.  Additionally, if there is an edit war in a post, the mods are generally going to side with the post author in any cases where the post author isn't intentionally vandalizing their own posts, or otherwise violating site policies with the version of the post they want.  (This is a good example of a situation where a mod would almost certainly side with your wording over other users' if they were brought in, although that wasn't necessary here.)
So all in all, I'd say that this is a good example of a situation showing the system at work, and working well.  Lots of people were enabled to add value, one person was making a harmful change, but the system was able to work around it and reverse it, and the post has settled in a good spot that's both very clear and in line with your intentions.
