8 should be just fine. They definitely will not be too much. *Might* end up being not enough, but it depends on which orchids you put in there, and how close you mount them to the lights. It's next to impossible to leaf burn plants with fluo's unless the leaves/flowers actually touch the bulbs, so don't worry about that. Just see how it goes. If the leaves are growing nice and compact, not stretching out and getting pale in colour, and if variegated leaves are keeping their colour/variegation, then you have enough light. Some leaves will get a purple tinge the indicates plenty of light (but not too much). I think you'll be just fine. BTW, what kind of bulbs are they? Cool white? Daylight? If either one of those, then they'll be good.

Just about any chandelier, semi-flush mount of flush-mount light will work there. You don't need much light in a foyer, since it is not a work or living space, so really the only factor is sizing it so it doesn't look too small or too large for the space. I'd probably go with a medium-sized chandelier for that space, one about 2 feet in diameter and hanging down about 2-3 feet; I'd also put it on a dimmer if it will be on for any significant amount of the day. But that's just me. Go with what looks good to you.

I'm curious, too. I have a large window directly behind our vanity and am ready to redo in there. The lighting is a problem. My windows face east. No neighbors, so we don't have window treatments. Currently, we have sconces and overhead lighting.

Ok then you can use an entry fixture about 18” round or square and you can go taller if you find great fixture. Options will depend on budget of course. You will want all 3 areas to play well together. You could use a semi-flush fixture in piano room with aged brass and black detailing. A bit of more casual look for that room. With your ceiling height in entry you could go higher for some drama if you wish. What is ceiling height in piano room? Pretty home.