I'm planning my 2nd home birth for any day now. My first was born at home 5 years ago.
As for keeping the house clean, the midwives really won't care (as long as it's not truly a tip and unhygienic and unsafe). But we personally have a cleaner (nothing to do with birth, just we work too much and don't have the time), so she's kept on top of the deep cleaning and we've just spent a few weekends doing some tidying up and some DIY projects to stay on top of it. Even if you can't afford or don't want a regular cleaner, hiring someone to do a deep clean before baby will make such a difference, no matter where you birth. I'm on mat leave now and every morning I just do a quick pass through the house and sort out anything that's a mess. I particularly stay on top of the bedroom and bathrooms (I plan to birth in the bedroom). Just so if I was to go into labour that day, I've got everything in order in the morning.
I would have some snacks you can easily keep in the cupboard, especially things you want to eat, some biscuits for the midwives, plenty of tea and coffee. You'll probably be planning a few meals for after the birth anyway (this applies no matter where you birth), so get in a few days worth of food that can either go in the cupboard or be frozen. I have about a week's worth of freezer meals made and then plenty of snacks stored away (dried fruit, nuts, granola bars, biscuits, chocolate, etc.) plus I made several batches of lactation cookie dough that I've frozen. So we don't have to stress about going to the shops right away. I have coconut water (it's isotonic) and dates and a few energy gels for myself in labour, which is what I ate last time and it worked well.
Where you birth and if you want a pool is just a matter of personal preference. I had a pool the first time, but didn't like it and only got in for a few minutes. I'm not having one this time at all. It just has no appeal at all for me to birth in water. I was quite happy walking around last time using a TENS and that's what I plan to do this time. I'm planning to give birth in my bedroom, which I did last time too. There's no way I would have wanted to walk up the stairs after in order to lie down and our sofa isn't very comfortable, so I want to be close to the bed so I can climb in after.
The midwives will advise you about when to call them. Generally, once you're in labour it's good to let them know you are, even if you don't need them. It means they can plan ahead for what they'll do that day. So I'd call as soon as you're fairly sure labour is starting. Then it will take about an hour or 2 for them to actually come out to you from when you first call (unless you live next to the hospital, we're like 20 minutes away). So I would generally aim to call when you think you might need them in about 2 hours. With my first, they said to call for them when I was in established labour (contractions lasting 1 minute and 5 minutes apart). I actually called them then just to let them know I was in labour (my contractions started at about every 5 minutes from the start), which was around 4:30am. I called back about 6:30am when I actually thought I might need them soon (at 4:30 I was comfortable and just wanted to be by myself). The shift changed at 8:30am, so I asked them to wait and send the next shift. They actually arrived about 9:30. My daughter was born at 2pm. Depending on how you labour or how fast your first was, you might want them sooner or later though.