Actually, they have a little difference 领 means receive, so "receive a package (from somewhere)" makes sense. 取 means go and get, so you can also go out and get the package (from somewhere). Normally it is interchangeable. 原来 means unveiling the real situation, something is proven to be...., something used to be... or originally 本来 means from beginning, originally, at first and 'of course'. So you can see they are only interchangeable when refers to origin or the beginning.

Normally you won't correct them cause it is just not that strict in daily life. Like you can say "How ya' doing" to your friends and they can understand. But you will never say "how ya' doing" when you meet the Presidents in a nuclear defense conference even they can understand you.

Whereas, while could be interchangeable only as conjunctions expressing contrasts. Whereas cannot be used when it refers to time duration. Whilst is more formal than while and they are interchangeable.

〇 is lower case of Chinese number. 〇一二三 零 is upper case. 零壹贰叁 However, people use 零 more instead of 〇. Example: 你住哪个房间？二零四。 it is not really a big deal if you use 〇 here. But it feels weird in normal conversation. 〇 now is only used in formal date writing(like invitation from somewhere) as Jack's example. And only in financial situation the upper case is used.

First is the punctuation. Second you could break one sentence into several to describe the surrounding better. I wanted to write my tastemate(I don't know what you mean by tastemate, maybe current situation?) for my family to read(actually you don't need to say this letter is for reading) after my migration from about 6 months ago. Now it is 26 March 2018, my two brothers are watching a movie on laptop and I am writing this letter to you.

It could be a good assistance resource. However, it is not a textbook for systematic learning.

Yes!

So it should be: The bike is not safe to ride. :p