Two rumours run actually.
1- Taito did not sell the rights of Liquid Kids.
2- Ocean thought it was not enough quality game.
Personally I think they didn't have the rights of the game. It wasn't the first time we started or finished a game without already having the legal rights.
It was very pleasant to work at Ocean France, it was my first real job and I had learn a lot, and meet some interesting people.
Many many many !! Already in this period, arcade machine had lots of graphics capabilities and Amiga worked hard to follow. There was lots of data to convert and many levels to finish.
For Liquid Kids, I had quickly done a reverse level design where all the friendly and monster sprites was referenced with each frame and size of sprite for every sprite. Like these:
The level was quickly drawn too:
We have 32 colors in this release so 16 was for all the Sprites and 16 for all the level's blocks. So we did take some liberty of graphic design for some levels.
No we never had any contact when Taito. I remember that Operation Wolf was the only one game where Taito sends us the graphics data. All the arcade conversion at Ocean France was done only with eyes spotted on arcade screen, and hands spotted on the mouse.
Yes it was the good rate of time but often we worked with only one or two artists and one programmer. On lots of games I did in Ocean I was alone on it.
All graphics on Liquid Kids was created with an internal Ocean (England) software "Sprite Editor" and "Map Editor" working on Atari ST.
Here is a screenshot of Sprite Editor:
Here is the Map Editor: 
Pierre Eric was the music convertor on somes games in internal team and Jean Baudelot in Freelance. Pierre Eric worked on a sound tracker and with synthetiser, Jean Boudelot too. For sounds effects I don't remember.
Yes, I'm actually in a development studio near Paris.
"Secret of monkey Island" and definitely the best plane game ever done "F18 Interceptor"