Second baby - baby shower

It's not traditional to have a shower for second babies in my family, and we don't need much, but....my sister just offered to throw a pre-baby lunch (inviting only close family members). I think we're going to make it a fun afternoon of making baby/cleaning supplies (I'm an essential oil addict) She wants to know if there's anything we need, but I feel really weird creating a registry for the 5 or so items we planned to buy. Any thoughts?