There was no kanji removed in the most recent update, only vocab.
Yomichan with InnocentCorpus gives frequency 92 for both words, which is very low (though not obscure). This means that in the corpus of 5000+ novels, they only occur 92 times. They seem like words that are even rarer outside of books. (For reference, 日本語 is at 10,000, とろ火 = low flame is at 72, and 私 at 950,000. I personally consider anything below 100 rather rare, above 1,000 common, above 10,000 very common. Though frequency ~50-100 can still be worthwhile, just not a priority)
I really recommend using a frequency source like this. Google results are problematic, as plantron said, you can also get chinese results by googling sometimes, and just dictionary pages. Actually i’m not sure how valid google results are as a metric, but they’re definitely not clean.
(you could also take other sources like twitter posts or movies or wikipedia, by the way)
Frequency 108 in InnocentCorpus, again very low, though not obscure.
No frequency in the InnocentCorpus at all. Either a mistake, or very rare.
But an alternative form of this, れんれん, has frequency 7, extremely low.
Maybe the google results are mostly tweets by/at twitter user 漣々 (@renrenillust) 
(choosing a rare word as a username is pretty neat, right?)
Yup, this has frequency 10734, so if i had to choose, i’d definitely put this in instead of the words above.
I just made a script that inserts these frequencies into your Anki cards, that’s why i like this topic currently