Regarding the Bonus Topic for Idioms...
Is it actually Spanish language idioms? Or is it just English language idioms translated to Spanish? The latter, while fun, wouldn't be very useful as a beginner in a new language. It's hard enough to get your point across :).
It's Spanish idioms, I don't think any are mere translations of English idioms. And the lesson is hard as hell. Good luck!
For nosralmada, here's a teaser:
Borrón y cuenta nueva (literally: Blot/blemish/smudge and new account)
This one has a lot of accepted translations, according to the discussion:
Let bygones be bygones.
Wipe the slate clean.
Water under the bridge.
Forgive and forget.
I like this lesson. and some of them over-lap with what i learned from the Memrise lesson "350 Spanish Sayings".
Just my 2-cent advice: Get out of the habit of trying to translate a foreign language to fit what you're accustomed to en inglés. There are many expressions that we use that makes no sense whatsoever to people from other cultures. It would probably be really beneficial if you learned Spanish idioms for their perspective. Unfortunately their perspective can be either Spain, México, Puerto Rico, Chile, Argentina, etc. which may increase language learners' frustrations.
There are some cases in which the idioms are not literally translated. But I guess if the literal translation exists, it is used, even if not as common as other idioms expressing the same thing. Most of the discussions about the idioms are long and helpful, so check them out.