she has to be more solid and fights harder on each ball, defend harder and especially WORK WORK WORK
Easier said than done. Court sense, anticipation and footwork are all very poor; she's unable to keep the ball in play as soon as she's forced into an awkward position (actually, even her aggressive game is way too linear and only effective when she's in the middle of the baseline). She'll never be even a halfway decent defender. The only way of not having to play any defense would be to develop an aggressive ROS. Problem is, right now her ROS is so incipient I don't see how that can be done.
The dropshotitis has to go; I suppose it's dogma for players/coaches bred on clay, but with a success rate of 1/20 or something maybe it's time to reconsider. There are no set ways to win points on any surface; the best game for Caroline is the one that makes the most of her strengths and makes it tougher for her opponents to exploit her weaknesses, regardless of what the textbook says and/or the way you're "supposed" to play on clay or elsewhere.
The lack of confidence Iceland mentions is visible mostly on serve. Sometimes she goes for it, but seems terrified of DFing and often will just spin it in, even on key points. That's something that can be improved. At the level at which she'll play for the next year or so, having a solid serve will sometimes be enough to win matches.
Was Fontang picked by the FFT, or picked by Caroline's entourage/family and merely subsidised by the FFT? I suppose I know what they were thinking; his work with Chardy showed that he might have the required skills to develop a young player.