Hi Rosh, glad you found us and decided to share your story
Honestly, i think you're being toyed with...Man, her reasons for not wanting to meet with you are straight out of the "BS-ing 1.01" manual, just read them again out loud and maybe you'll realize how childishly stupid they sound....and that's just the cherry on top. Think about it this way, she's getting all she wants from you without having to commit to anything: she knows you want her (ego boost), she knows you're not seeing anyone nor planning on doing so (double ego boost) she has a "on stand by" ear to listen to all her crap, a shoulder to cry on maybe (i'd still put this on "her crap" as long as you're not dating her) -> and all this while minding her own business, while you are stuck in a "waiting to make your move" routine and looking up to her for a green light. Rosh, it ain't going to happen mate, life isn't a corny chicks flick...she came back only for the ego boost and it ain't something unique or uncommon. Probably she got rejected by someone and needed a refill station.
You were on the right track with going NC and therapy but Rosh, read more of the stories around here and be amazed how many people got tricked the same way you did, confusing a dumper's need for validation and selfish ego boosting for genuine indicators of reconciliation. Also, don't even get me started on the whole "need space" excuse you got at your break-up...search for an old thread of mine called "Nails in the Coffin" and you'll get the picture. To be blunt, from where you are right now, you'll only go down, never up to the position you desire....if she wanted you there, you wouldn't be here believing juvenile excuses and looking for hidden meanings.
Go NC, tell you sister to either cut the chatter or keep you out of the news feed. Sticking around benefits only one person, and it ain't you.