Create an new feature class with the same spatial reference as the polygons you are trying to dissolve. Then use a search cursor to pull geometry objects. For each row in your buffer feature class, perform a union to create a single feature.
import os
arcpy.Buffer_analysis(featureLayer , temp2, "0.5 Feet", "FULL", "FLAT", "ALL")
#get path and file name of temp3
temp3path, temp3name = os.path.split (temp3)
#create new feature class
arcpy.CreateFeatureClass_management (temp3path, temp3name, "POLYGON",
spatial_reference = temp2)
#iterate buffer attributes, pull geometries
with arcpy.da.SearchCursor (temp2, "SHAPE@") as curs:
for geom, in curs:
try:
#union current geom with all prior geoms
unionGeom = geom.union (unionGeom)
except NameError:
#first geometry, just assign it as union geometry variable
unionGeom = geom
#insert dissolved geometry into created feature class
with arcpy.da.InsertCursor (temp3, "SHAPE@") as curs:
row = (lastGeom,)
curs.insertRow (row)
...or without a new feature class, just dissolving a feature class with multiple features into a single feature:
#iterate buffers, get geometries
with arcpy.da.UpdateCursor (temp2, "SHAPE@") as curs:
for geom, in curs:
try:
#union current geom with all prior geoms
unionGeom = geom.union (unionGeom)
except NameError:
#first geometry, just assign it as union geometry variable
unionGeom = geom
#delete row
curs.deleteRow ()
#create insert cursor
with arcpy.da.InsertCursor (temp2, "SHAPE@") as curs:
#insert final union geometry
curs.insertRow ((unionGeom,))
arcpy.Buffer_analysis(featureLayer , temp2, "0.5 Feet", "FULL", "FLAT", "NONE")
(different dissolve type for the buffer). Worth a shot.