I figured I'd provide some information as it pertains to the upcoming release of Masque (currently in beta) that should help with transitions.

First, I've changed the signature of callbacks, like so:

If no add-on object is passed:

callback(Group, SkinID, Backdrop, Shadow, Gloss, Colors, Disabled)

If the add-on object is passed:

callback(arg, Group, SkinID, Backdrop, Shadow, Gloss, Colors, Disabled)

So in buttonThemer.lua, change line 8 to:

    local Masque, MSQ_Version = LibStub('Masque', true)

Change line 12 to:

            if MSQ_Version < 80100 then
                local _, group, _, _, _, _, disabled = ...
            else
                local group, _, _, _, _, _, disabled = ...
            end

Additionally, the value of .SubList tables is now actually a reference to the sub-group, so for the sake of backwards-compatibility, change line 51 to:

        for groupName in pairs(Masque:Group(AddonName).SubList) do

Unless you want to do a some version check magic there:

    local Masque, MSQ_Version = LibStub('Masque', true)
    if Masque then
        if MSQ_Version < 80100 then
            for groupName in pairs(Masque:Group(AddonName).SubList) do
                Masque:Group(AddonName, groupName):ReSkin()
            end
        else
            for _, group in pairs(Masque:Group(AddonName).SubList) do
                group:ReSkin()
            end
        end
    end

Another thing is that Dominos internal "themer" only seems to apply as a back up for Masque being disabled. If that's the case, this is no longer necessary as Masque now includes the default skin. So if Dominos is disabled in Masque, it reverts to how it would look if Masque were never loaded.

Lastly, Masque now accepts "default" skins that a given add-on will revert to if its groups are disabled in Masque. Authors simply need to add the skin like any other skin and Masque will use it when a group's disabled. I've created a skin that you can include with Dominos that will handle that. Poke me!