A good midwife will help you get started breastfeeding and cleanup after the birth and maybe help with getting you something to eat afterwards and into the shower and all that. Some midwives always have an assistant with them. Maybe you have a friend you'd like to have at the birth to help out as needed? If you end up needing a lactation consultant for help with breastfeeding, it may be good to meet one now. Try getting to a La Leche League meeting at least.
Ask the prospective midwife about what her style is. Is she hands off? What does she do in a typical birth? How does she handle emergencies? How many women has she transferred to hospital? Will your current CNM back you up if you need to transfer (ask the CNM, not the lay midwife)? What are her general views on a birthing woman? Be sure to let her tell you, don't offer your opinions of what you want first.
As far as the bedrooms being upstairs - you don't have to give birth in a bed, you know. I gave birth in a beanbag chair on the living room floor and never even wanted to go upstairs to the bedroom, even though the bed was made with 2 sets of sheets and the plastic sheet. Of course, when I went into labor, I didn't want to be upstairs, I just wanted to be downstairs, don't know why. The dogs you may want to arrange for someone to come get. Or just keep them out of the room you're in. Can you put them outside, maybe? Or don't worry about them at all. Are they big dogs? If they're little, I can't imagine they'll be in the way, if they're big, they might not be interested at all. My mom's german shepherd spent our entire labor & birth outside. I don't think she remotely cared about what we were doing.
The small water heater... Well, you'll need to run all the hot water first. Then boil the cold water, I guess. You might really want to think about having a friend at your birth to help with this sort of thing if you think it will be useful and not interfere with your process. I know a lot of women want very intimate, personal births, but I personally like having all the support of several people. That way I get the immediate, physical support of my DH and a friend as birth partner, then there are other people there to keep the washcloths cool, the compresses hot, get the pool filled, warm the blankets, etc. Of course, one husband and a midwife can probably handle all that fine as well. Ask the prospective midwife what she thinks and go with what you really feel would be good. I can't tell you how your birth will go... Everyone is different. Like I said, lots of women want to be alone, others like extra support.