Thanks for expanding. The state of the solver wrappers is a known issue, which is why we recommend non-experts to use JuMP rather than low-level wrappers. If you expect to have tidy, documented solver-specific wrappers for one of the commercial solvers, I would recommend using an officially supported interface. We’re hoping that more commercial solver developers will create and support Julia interfaces soon, like Artelys and Mosek have done. As you might understand, the JuMP developers don’t often feel strongly motivated to do unpaid work that benefits only users of a particular commercial software package.
For cross-reference, this discussion also continued at Solver-dependent callbacks in JuMP -- How to do it right? - #5 by miles.lubin.