I found my list of needs was a lot like yours- and far far shorter than the recommended homebirthing list. my midwife also showed up w/ many necessaries.
sitz bath- yes!
and herbs and arnica
i froze pads soaked in witch hazel and used those for soothing my poor bottom- for about 3 days.
disposable underpads- i had one pack w/ my first, and we used a lot of them b/c my water broke and she didn't come for another 6 hours. i used maybe 3 with my next homebirth, and the midwives used them when i was pushing. it wasn't that messy. i know that sounds odd, but it wasn't.
i had a shower curtain on a mattress and some old clean blankets, a yoga ball to sit/rest on, and a husband bringing me iced kombucha and sparkling water, and that was about it for the entire thing.
maybe some massage type oils for the actual labor- massage of both my lower back and shoulders really helped me relax and dilate.
i birthed on a couchbed the first time, and on a mattress on the floor next to the couch the second time. my husband sat on the couch and i squatted hanging on to his knees the second time, and that was a great position for me. i like being on a soft surface when laboring as i doze off a lot and like to lay down sometimes (i seem to be sleeping a lot when my water breaks).
i didn't worry about nipple cream and such as i had been nursing throughout labor- but anything to help soothe your bottom and skin and make you feel good afterwards is a good idea. a couple of nice/pretty/comfortable nighties, (b/c i sweat through a lot the first few days postpartum due to hormones), towels, lots of pillows for being comfy after birth, and a lot of food in the freezer if your husband isn't a gourmet chef. i pretty much call the bed my home for a while after birth and just try and rest to recover.
my husband and midwives did clean-up and it didn't seem like a big deal- there wasn't a lot of blood, though i was shocked at how much amniotic fluid i had during my first homebirth (and it smells exactly like semen) and it kept coming. old towels and blankets on had was great for us for most things.
it was a much easier transition than i expected- one baby was born at 12:30am- midwives were gone by 2am, and in 2 days we had really started flowing with it. i think that's one of the beautiful things about homebirth. i don't remember how the other birth worked b/c i fell asleep w/ the baby afterwards!