Need help with a Turk's Cap bonsai re-potting

[skinny]

I am fairly new to bonsai and have a Mexican Turk's Cap that needs re-potting. I have been fighting a battle with mealybugs, had some success, but I think there are things in the soil that a preventing total eradication. I found white nodules under some dead moss, and attaching picture. Also some small silver cylinder shaped crawling bugs that only move when the soil is disturbed. I'm attaching a picture of the white nodules (about 10x magnified).
My questions:
1) What type of soil should I use during the repotting? I was leaning towards either an entirely non-organic mix, or non-organic with a little organic (has small pine bark pieces) mixed in at 75/25 ratio. (note: I live in Florida).
2) I am in the right forum for this plant? I can't find any information on it. It does produce flowers, so thought I'd start here.

Thanks for any information/tips.

 

[Firstflush]

I’m unfamiliar, search here and the web using the botanical name. Likely get better results.

Malvaviscus arboreus var. mexicanus

 

[Shibui]

I'm not familiar with the common name either so cannot offer suggestions for that particular plant but searching indicates it is probably one of a number of Malvaviscus sp also known as mallows.

Mealy bugs hide well so very hard to eradicate. Any you miss soon breed up to replace the ones you kill. Woolly aphid is similar and could even be what you have. They live on the roots as well as above ground so treating above ground only solves half the problem and the underground ones just breed up and re-infest above ground.
Systemic insecticide treats both above and below ground and gets all the bugs you cannot see so much ore reliable than contact treatments.

Not entirely clear what the white things are but my guess is probably some sort of fungus which may be good or bad. Very hard to tell from a pic. There are lots of white things that live in soil. Some are a problem while others are very useful.