The given value (2kg) is approximate and won't be known exactly until the container is recovered. Knowing the typical composition (including density) of Moon rocks and the volume of the container, one can easily foresee the average mass of the samples, but the actual mass will depend on the local composition, granularity (amount of empty space between grains)...
I don't think there are any more beyond those you listed.
There would be three reasons to perform a docking:
Bringing something back
Assembling a larger structure
As no assembly as taken place beyond Earth orbit so far, 3) is ruled out.
2) I relatively simple to cover, since the only things worth the high cost of recovery is humans ...
This answers the question as originally asked:
How many docking operations have taken place beyond Earth orbit?
Zero. All of the examples listed took place in Earth orbit. The moon orbits the Earth, so anything done in its vicinity is still occuring within Earths gravity well.
per Wikipedia, Beyond Earth Orbit (BEO)
require[s] an insertion into a ...
Just checked from the JPL Horizons website. It seems that it is in fact still there. I also looked at the JPL Small-Body Database. Looking up Toutatis, it says it was last updated in 2003. It seems very unlikely that it was specifically deleted because China wanted to send a spacecraft there.
In 2014 China and Argentina signed an agreement that allowed China to establish and operate a deep space station in Argentina.
According to Reuters, the Chinese military runs the station in Argentina. The site is on a 200 ha compound, in a remote part of Argentina.
While it still has access to an Australian space dish, at Yatharagga in Western Australia, ...
There is a Chinese run ground station in Swakopmund, Namibia.
This station is part of the "Chinese Tracking, Telemetry, Command and Communications System", which has similar stations also in Karachi, Pakistan and Malindi, Kenya.
See https://en.wikipedia.org/wiki/Swakopmund_tracking_station for more information.