Yes you absolutely could grow it in the house...I'm in Alabama....I didn't need a special environment, I only have one sunny window in my house in the winter too...I just set the trays in that window, they don't seem to need a ton of sun because I also kept one tray in a different room where the sun was not coming in directly and that one also grew readily, though it was not quite the deep green as the ones who got the little bit of sun.
I also keep my house on the warmer side both summer and winter bc I have a very old frail cat, so it's usually in the mid to high 70's inside and it all just grew like mad..
from what I read the mold is from using too thick of layer of seeds, the idea being good airflow around the stems and not overwatering will prevent mold just fine, so far that seems to be the case. Once the roots grow down I've been watering in the tray it at the base and I think that may help the mold issue as well.
Here is the short video of the juicer I have,
the lady showing it uses both the suction and the table clamp but so far I've just used the suction and it is really sturdy until you release it.
I guess it would be considered a masticating juicer even though it is manual? It is really, really easy to use, I'm even happier with it than I was anticipating! When I'm done a quick rinse of the parts and let it dry in the dish rack, I've been adding the grass fiber it spits out into my compost bin.
I was not familiar with the vitamix so I looked it up, some people say you can't but this lady shows how she does it- I've seen similar videos with blenders, it seems to work ok as long as people mince the grass up small so it doesn't wrap around the parts and mess up your machine..
Hope this helps! I know it's doing something to help me, bc when I drink the juice I get that same sensation I get after taking anti-lyme herbs, so lyme doesn't like it, which makes me love it all the more.