I bought the NJStar wordprocessor for Japanese a couple of years ago. It's quite good.
You type your Japanese words in Latin characters on your Latin keyboard, and the text in displayed in hiragana-s.
Once your sentence is finished, you highlight the hiragana-s that should be replaced by katakana-s, and click on this option.
As regards words to be written in kanji-s, for a given word, you highlight the corresponding hiragana-s, and put the problem to the dictionary. It will come up with all the possibilities stored in its memory, and you pick the one that fits your text.
You can enter kanji-s directly by searching for them in the facility where they are sorted according to their Chinese radicals. The process can be long, but often necessary because the dictionary doesn't contain everything.
Once your text is finished you can copy it and paste it on a MS-Word page. There it is treated directly as text.
You can do the same with WordPerfect. Unfortunately WP will treat your Japanese text in kanas- & kanji-s as a picture, so you have to paste it as such, then position it clung to the page, a paragraph or a word, the latter being useful when quoting a Japanese term or name in a non-Japanese text. The best dimensions for each kanji are those of a 0.40cm square. The only advantage of Wordperfect is that the characters are the originals generated by NJStar, and they are both clear and beautiful.
I didn't buy the Chinese version. A couple of times I needed logograms that were not supplied by NJ-Star Japanese. I printed enlarged versions (10 x 10cm) of logograms that had the required elements, cut them out with a pair of scissors and assembled then to obtain the missing logogram. The final step was to scan it to insert it into the text.