The M40 should be just enough for that. To my knowledge you cant use a 6 kW bulb with one, only 2,5 and 4 kW. It probably wont create blindingly bright light rays, but as you said the house is facing north, you should be good. It also depends what you might be seeing outside the windows? If you are looking at white walls hit by direct light, you will need a ton of light inside the building to keep the contrast ratio reasonable, if you are just looking into green canopy you (again) are of to a good start.
I would not expose for the light level of the window or outside the window. To my experience, If you expose the outside 3 stops over, you most of the time get a good result, event though you might want to increase that level further if you want to go for that sunlight blasting in kind of look.
In terms of haze: always use less than you think you need. With haze its very much like slowmotion: its easy to overdo it and go to far with it, because it just looks "cool". Try to restrain yourself with that as much as possible. Have a real hazer and not a fog machine. Technically you can get more or less the same results with it, but it eats into your valuable shoot time so much, because it takes way longer between takes to get it to that same level again, because it takes so long to settle and not look like fog anymore, even if you fan it like hell.
For the angle: that depends what time you want to emulate. If there isnt a special time called for, I would try to have them reach so far into the room that they end lower than the talents face, which gives you the opportunity to light their faces softer than with just the harsh M40 beam. If you are unsure what looks good, try to have the haze already set when deciding on the final position of the M40 and have some stand ins, so you know, what the light does. I would also experiment with warming the M40 up a bit, with an 1/8 CTO or CTS. For me, that takes off a lot of the unnatural edge they tend to have.