well... first what i need to say is that you have understood it quite well.But there is sometihing detailed need to be explained. i conclude your questions as follows: 1、what's the difference between 来着 and过、了? 过and了 are usually used together to indicate past tense. example:我吃过饭了. when it indicates past tense,来着 ususlly follows a verb and a 刚才 or 刚. 2、whether the last example has to do with past tense or the idea of 'just now'? no,i doesn't. this time it indicates question.it means asker was not sure about the answer. 3、”Also why do you need to add 来着 when 刚才 clearly tells us the action just happened? “ you don't need to. 来着is not necessary here. But until you need to add 了，the sentence makes sense.like 他刚才说了什么？ you can regard them as two patterns. 4、“他还哭来着呢。For all we know, he could have cried over the movie years ago!“ this sentence is kind of weird .Anyway, 来着 here means he did cry,though he might cry long time ago. i list several indications of 来着 for your reference: 1、not sure 2、past tence 3、emphasize（like他还哭来着呢)

It is not only about a recently happened event, but about all the past action or state. In this sentence : 什么时候放盐来着？It indicates that 什么时候放盐 has been told or mentioned before, but the speaker forgets now. Let me give you similar examples: 他叫什么来着？It indicates he already told you his name but you forget now. 他去年冬天还回家来着。 你忘了爸爸小时候怎么教导咱们来着？

As I guess, 来着 may be a Mandarin word, it hardly appear in Cantonese or other southern dialects in Guangdong. If you can read Chinese well, I can send you two essays which are specially talking on the usage of 来着. I am not specialist to explain this word but I can find if it's odd being put in a wrong place.

I think it's just an emphasis to show your emotion. I seldom use it, only something like 这是什么来着(what exactly is it). And in this way I'm trying to ask for more detail and I hope people would give me some answer about how does it made or what made this thing happen.

我在这里说过许多次了，汉语没有时态，放弃“着、了、过”是时态的标志的观念。可惜没有几个人相信这一点。所以，你的纠结是一定的！！！！！！因为它根本就不是时态问题，你硬要那样理解，当然会困惑。用“来着”可以表达过去的事，并不代表它表达的是“过去时态”这完全是两回事。它的使用，和有没有“刚才”，“刚”、“刚刚”也没有任何的关系，它根本不表达过去了多长时间，它表达的是“这件事曾经发生过”。比如：这是什么来着？严格的说并不是what exactly is it?这样的含义，因为这句话的含义中告诉了我们，问话的人曾经被告知过这个东西是什么，只是他记了，所以现在又问“这是什么”，这就是“来着”所表达的含义，它和时态没有任何的关系，它表达”XXXX来着“中的“XXXX”曾经发生过。就这么简单。你怎么才下来？我吃饭来着。表示“我下来之前这段时间在吃饭”。这就是为什么要用“着”，用“着”表示“进行、存在”等等含义，都是着的基本含义。比如：她来哭来着，这里的“着”表示“存在过”，而“存在”是从“进行”引申而来。“哭着”就是正在哭的意思，“哭在进行中”，因此“她还哭来着”，“着”就表明当时，她一直哭，甚至是曾经持续的哭过。如果把“时态”抛开“，你会发现汉语其实很简单，只要深刻理解每个词语的含义，把这些含义正确的组合在一起就行了，基本无需考虑”时态“问题。