Sorry, should be better now. I removed the kanji overlaying the katakana version of the terms. The label next to them is not exactly ideal, but it'll have to do for now. Thanks!
The top two have different kanji readings (one has 無, one doesn't). They are listed separately in the original dictionary that renshuu pulls from, so they remain separate here.
That being said, what did you search on? When I searched, they all got pulled into a single entry with "Alternate kanji" markings.
That screenshot is from Firefox on Windows 10, but I get the same result in Firefox on Android. Other entries with Alternate Kanji seem to work okay (I just searched for あたたかい to check), just not this one I guess.
Definitely an adverb. I changed it, thanks! Since they have different "spellings", they'll be left as separate (but grouped together in the dictionary) so they match the dictionary that renshuu is based on.