simply sounds like youre trying too hard.. as far as im aware killing a ficus without destroying the roots is nearly impossible, ill leave em out into subfreezing temperatures and as long as it isnt prolonged thye bounce back all bushy and small.
hibiscus is a different story. pop the buds off before they flower it seems to drain them. you have to balance wet and dry. it kind of just takes a bit of trial and error, i got a hibisus earlier this year and it immediately began flowering and went to shit. looked sickly ill. even will full indoor sunlight in my kitchen, stuck it in a cham cage and it bounced right back. of course it isnt uber bushy but it has a real nice amount of foliage.
i think your green thumb is trying too hard. or you might not be good with plants. i tend to advocate keeping live plants in cages becuse if you cant keep the plant alive youre likely going to have issues with the cham.
fresh soil, bigger pots and aeration in the soil is great, especially if its a very wet environment, pearlite or vermiculite will do just fine, just cover the surface wilth a later of fresh compost, and large stone or small plants (i use small plants like spider plants to dissuade them from eating soil) or even moss or grass if its lit well enough in the bottom. big plants my cages tent to steal all the light from the canopy.
good luck have fun and dont worry too much. too much worry can and will be detrimental
oh well.
