So I tried to modify tplink.py to return
{"emeter":{"get_realtime":{"current":%c%,"voltage":%v%,"power":%p%,"total":0,"err_code":0}}}
For sonoffs, Obviously with replaced tokens, but I guess you don't really call tplink.py from your script, but handle everyhting internally or maybe you do call some commands before
{"emeter":{"get_realtime":{}}}
which I also should fake output ? I'm to lazy to sniff the traffic right now

I ended up ordering a plug. It's hard to develop and test without one. I should get it today so tomorrow I'll start development.