So are gravitons related to higgs bosons in the same way? Or are gravitons, assuming higgs boson === inertial mass, more like the difference between (higgs bosons aka inertial mass) and gravitational mass (thus unrelated to / independent of higgs bosons)?
We've only measured gravitational waves directly last year. The theoretical graviton is still ways off - the energies required are incomprehensible to mere mortals.
the graviton is too small to be observed directly by our machinery.
if you can provide a detector the size of the solar system, proving/disproving its existence will be simple.
we could derive anything from first principles if we knew them. theres nothing probable about that. thats the whole point of first principles. do you want me to call you captain obvious?
Mass is essentially rest energy by another name. The presence of a non-zero Higgs field gives certain elementary particles that would otherwise be massless such a non-zero rest energy.
In contrast, compound 'particles' (hadrons, atoms, chairs and tables, ...) only gain a miniscule amount of mass from the Higgs mechanism: They are bound states of interacting constituents that are whizzing around, generating ripples in various quantum fields (sometimes described as clouds of virtual particles), with the biggest contribution by ripples in the field of the strong nuclear force.
Now, in quantum theory, any field comes with associated particles, and for the Higgs field these are the Higgs bosons, and for the gravitational field these are the (conjectured) gravitons.
While gravitons would be intimately related to how gravity works at the quantum level, the relation of Higgs bosons to inertia is rather incidental.