Oh no! Poor hibiscus! Thankfully, as you thought, these are just aphids. I think but I'm not certain that the long black ones with wings are thrips. You can use an insecticidal soap to get rid of these pests. Make sure to spray the undersides of the leaves as well. Spray until the leaves are dripping and move the plant into the shade for a couple of days (any pesticides may burn the leaves when mixed with the sun's UV rays especially when they are new and tender). Also, if you have access to a garden hose, spray the leaves with a good stream of water to dislodge any other pests. Good luck!

thanks very much

The fellows w/ wings are also aphids. Hope they're gone by now.

thanks, I thought so. I ordered ladybugs and they seem to be enjoying chowing down on the aphids :-)

thanks!