Teo1. I am living in Taiwan for six yearss. Incorrect usage.
2. I have been living in Taiwan for six years. I started living in Taiwan six years ago and am still living there.
3. I have lived in Taiwan for six years. Possibly means the same as no. 2, or could mean that once in the past I lived in Taiwan for a period of six years.
Do you agree that #3 could mean that once in the past I lived in Taiwan for a period of six years?
I agree that it's arguably possible, but anyone who wishes to convey that thought would be well-advised to to make it less ambiguous.
People often say things like, "I have been living in Taiwan off and on for the past twenty years." In this version, the total accumulated time spent there is unknown.
Absent previous context to the contrary, a native speaker would probably assume that both 2. and 3. mean "During the past six years I have been living continuously in Taiwan."
"In my youth / during the 1990's I spent six years living in Taiwan." (simple past)
If you really want to use "have" to indicate a period in the past, you should probably put the duration in a different clause or sentence.
"Have you ever lived abroad?" "Yes, I have lived in Turkey, in Iraq, and in Peru."
Switch to simple past for the durations: "I spent six months in Turkey, two years in Iraq, and six years in Peru." "I lived / had lived here in France for twenty-five years before moving to Turkey."
Regards, - A.