It's been awhile since I looked at this but from memory what was fascinating was that for the Imperial badges, the plain tung leaves were for the higher ranks and the peony flowers for the lower ranks, yet when it came to the Republican badges, the order was reversed! So perhaps Yuan Shikai and his friends wanted the more showy peony flowers rather than the plainer tung flowers.
And you're right, the Republican Rank and Merit very rarely appear for sale which is peculiar since practically every minor regional warlord received one. Perhaps it's the opposite of the Double Dragons where almost all the awards were to foreigners who then expatriated these overseas where they might be preserved from war and revolution. Very few if any foreigners received the Rank and Merit. They do very occasionally appear in China.
The other fascinating thing was that for the Imperial badges, the actual and metaphorical "centre" of the badge was yellow for earth and the Emperor, whereas for the Republican badges, the centre became red for the Han Chinese!