I personally wouldn't set out what you'll do in a 2 hour clean. I'd just say you're available, then when people phone, go and visit the house.
Your list could be done in an hour in a totally clean, uncluttered, minimalist apartment. But it'd take all day in a large family house where you have to move piles of stuff just to get to the floor. All the cleaners we've had have always come for an initial appointment to assess the house, before deciding how many hours it would take, or else if the home owner knows how many hours they want, telling them what they could or could not get done within that time.
Might also be worthwhile thinking about what you won't do - most of ours won't touch the inside of an oven. Some have happily changed bedding, put on a load of washing, done ironing. Others would prefer not to do that.
Cleaning stuff - most of ours use our own cleaning products, which is obviously cheaper for the cleaner but might be frustrating if I'm running low on a particular product. If you're going to bring your own, will that include a Hoover, mop and bucket, etc.? In which case you might need to get electrical stuff PAT tested.
I've always paid cash, but I know some people prefer bank transfer or similar.
Make sure your hourly rate covers the cost of getting to each house, and if it's an urban area, don't forget the parking costs if relevant.
PreChristmas clean is an excellent idea. And if you don't mind really getting into the nitty gritty bits then you could look at end of tenancy type cleans too - deep cleaning and occasionally truly disgusting.
Our cleaner cleans houses when her children are in school, and takes in ironing for when they're at home; extending her working hours without having to pay for child care. Looking at her spends (she's keen to show off new bags/boots/etc.) she has more disposable income than I do these days!
Don't underestimate word of mouth and decent references - got any friends you could do a practice run on, maybe a one off pre party clean in return for some testimonies and recommendations?