I guess "grainy" pictures are either related to the quality of the sensor or the image processing/ compression software, and not related to the quality of the glass - however, Canon has better glass than Sanyo, no doubt about it.
I find my Xacti C4 (4 MP) pictures (outdoor nice bright day) nice and sharp (in fact, better than my other camera, Minolta Z10), but I have not printed them to see what they are like on photo paper. The only difference between mine and yours is the image sensor size.
I think ISO 100 and 200 should produce little graininess, but they are only good for bright outdoor light. If you fix the ISO to these when shooting at low light, the shutter speed may get too low and you get blurs. I guess you have to test it out youself to decide what is best for what situations.
Yes the remote is for playback control only.