If the opponent plays Hidden Blade on my Hwei at a battlefield, and I Star Cross my own Hwei, will I still get to draw 2 cards?

No, you do not draw 2 cards.

Star-Crossed resolves first (LIFO), returning Hwei to your hand. When Hidden Blade then tries to resolve, Hwei is no longer a unit at a battlefield — it's an illegal target. Hidden Blade cannot determine "its controller" from an illegal target, so the draw effect fails (Rule 359.3.e.12). This matches the direct ruling in FAQ #11238 and #5879.