I think all parties involved would have discussed the plan ahead of time . Leia showed from the beginning that she can handle herself and I think if Luke had expressed Jabba’s reputation and treatment of captive women , Leia would have told Luke that she is a grown woman and can handle herself . And where was it stated that Luke had sole input in devising the plan ? Perhaps Leia knew the risks and decided how to proceed in her part herself anyway . Still , the plan as shown in the movie was convoluted for sure .
Well, let’s say Leia’s role was to (1) deliver Chewie to Jabba, (2) unthaw Han, (3) get caught herself so she ends up on the sail barge with everyone. This is kind of hard to buy, because the way the scene plays out (when Han says “I know that laugh…”), Leia seems to act like getting caught was an unexpected bad outcome. At least that’s my interpretation of the scene. But they also could have planned it so that Leia delivers Chewie to Jabba, collects 50,000 credits, and leaves. Then Lando unthaws Han, gets caught, Luke shows up, etc. Although we can infer Lando did lots of reconnaissance work, he never actually does anything onscreen to help. (But then I’m still wondering why Boba Fett doesn’t recognize him at some point, but whatever.) Maybe they chose Leia specifically because they knew that if she were caught unthawing Han, she wouldn’t be executed on the spot (unlike Lando), and would instead likely be turned into a harem slave.
Now, I’m sure Leia can handle anything Jabba does to her. She already endured torture from Vader and didn’t crack. But subjecting her to Jabba’s degrading treatment seems particularly egregious because it barely seems necessary. No matter how you look at it, the plan is ultimately to just have a Jedi show up and kick ass. So, how about this: Luke dresses up as a bounty hunter and delivers Chewie. Luke then unthaws Han at night and gets caught. Presumably then Jabba will throw him to the rancor, and the plan proceeds as usual. Alternatively, after delivering Chewie, Luke retrieves his lightsaber from R2, unthaws Han at night, gets caught, then just fights his way out. Leia shows up with the Falcon outside as their getaway. That alternative handwaves away how Chewie gets freed and makes many logistical assumptions, but either way, having Leia involved seems unnecessary when ultimately the plan revolves around Luke showing up, getting taken prisoner, and then getting Old Republic on everyone’s ass.