Leaves are large, flowers are larger, wood is stiff, with pithy center in twigs. Will not bend. They have been made into bonsai, but would have to be a very large bonsai. Your sticks would have to grow in the ground for 10 years or so.
As with any bonsai, working from older material is always best... But with all due respect I have to say your response is somewhat unrealistic in it's hopelessness. Let's examine what can be done with it from a work perspective and let her decide if she wants to try it... (which clearly she does)... and help her to be as successful as she can be until she decides to set it aside or is satisfied.
Leaves tend to large, but can be managed by thinning. In fact hibuscus will blast leaves off in a heartbeat if they get distressed by temp changes or drought. But it'll pop leaves almost immediately. But until these small trunks put on some size, I wouldn't be worried about trying to manage the size of the leaves.
The wood is very stiff... so you'll have to very gently wire new growth shoots... and I wouldn't bend any one too far... Growth tends to be very linear, so you will need to prune a lot to get any movement into it... but again, getting some size first would be helpful... Unless you want a little shohin like the image I showed. Though what makes that one so successful is the obvious age of the material used. Likely it was airlayered off of a old specimen.
It's all about the time one wants to invest...
Some practical questions for success... what kind of growing enviornment do you have it in? As an FYI they don't care for low light, or cold temps, and prefer higher humidity though they tolerate less.
Good luck!
V