Most important thing to attempt is to grab sheik and chain-grab her. You can space a SHFFL f-air her shield outside of her grab range and then f-tilt her.
To counter her approach, throw out some low angled forward tilt.
To botch her recovery, just hold onto the ledge and regrab the ledge right before sheik poofs so the poof doesn't hit you, then just normal get up from ledge (slightly flick up on your control stick gently). If Sheik recovers onto the stage, just run past her and b-air her off the stage.
If Sheik is spamming needles, just lightshield and wave-dash OOS towards her. She gives up her position on stage when she mindlessly throws needles against you.