In Classical Japanese, the auxiliary verb "-つ" ("-tsu") has a perfective function, indicating the completion of an action or process. According to Haruo Shirane's Classical Japanese: A Grammar, "-て" ("-te"), the ren'youkei or continuitive conjugation of this auxiliary verb, later developed into a conjunctive particle with several different meanings: (1) temporal/sequential connection, (2) parallel connection, (3) causal connection, and (4) existing condition.
I can see how a usage of a marker for perfective aspect could develop meanings 1 and 3, as these both rely on posterior or definite qualities, but my question is how do meanings 2 and 4 derive from such a form? 1 and 2 in particular seem to have conflicting definitions, the first meaning "and then", the second meaning "at the same time". Are there any explanations for how the meaning could shift in this way? And are there any papers that discuss the semantics behind the development of this kind of change (whether specific to Japanese or not)?