Difference in meaning based on position of modal verb Here's a child's essay [1]:

今天是元宵节，妈妈说，在滨江公园有猜灯谜的活动。她还说，看花灯、猜灯谜、还有吃汤圆是元宵节的民俗。
晚上七点半，我和妈妈还有亲戚一起来到滨江公园，人真多，非常热闹！那里没有猜灯谜，我好失望。但是我们放了烟花，还放了孔明灯和河灯，真是太有趣了！
我觉得最有意思的是放孔明灯。我先在上面写了“希望我学习100分”，然后妈妈把蜡烛固定在孔明灯上，我用打火机点燃蜡烛，孔明灯全都鼓起来时，就松开手，它就慢慢地升向了天空。我真希望能梦想成真。

The very last sentence translates in my perception to:

I really hope that it is possible for my dreams to come true.

I would have probably transposed the sentence moving the 能, like so (better yet, drop the melancholic note by substituting it for the firmer 会):

我真希望梦想能成真
I really hope that my dreams can come true.

Is my line of thought correct for the translation? Are both translations accurate?
[1] https://zw.liuxue86.com/z/3628756.html
Both are accurate. 梦想成真 is a set phrase, so using 能 before it is acceptable. Note that if it is not a set phrase you need to put 能 before the verb 成真 here, but because it is a set phrase, it is usually perceived/interpreted as a whole. 

You can also break it up and put 能 before 成真. Both are valid here.