There's no problem in terms of your new Panasonic TC-P65VT30 (excellent choice of TV, by the way!) getting a good signal from your Blu-ray player. I'm not entirely familiar with that model of Yamaha Sound Projector and what inputs it has. I took a quick look at the specs and the YSP 4000 appears to have 2 HDMI inputs and one HDMI output, 2-in/1-out component video and two each coax and optical digital audio inputs.
Specs say the HDMI inputs will pass through 1080p and 1080p/24, so there should be no problem at all. Just run an HDMI from the Blu-ray player to the YSP 4000 and then another HDMI cable from the YSP 4000 to the new Panasonic TV.
The specs make no mention of 3D Blu-ray support though, so if you want to play 3D Blu-rays, you first have to make sure that your Blu-ray player is a 3D player. Then you would have to run HDMI directly from the 3D Blu-ray player to the TV and use a separate optical or coax digital audio connection to go from the 3D Blu-ray player to the YSP 4000. That's only if you care about 3D though
I'm not sure how you get your TV signal. If you have an HD cable or satellite box, you'll simply run an HDMI cable from the box to the YSP 4000. If you are running an over-the-air antenna straight into the TV, the TV has an optical digital audio output that you can run to the YSP 4000 to get Dolby Digital sound from the TV.
Displays have well documented and defined industry standards. Every primary and secondary color had an exact coordinate position on the chromaticity diagram. White has a specific coordinate position. And the rate at which black rises to grey and then white is defined by the "gamma" for video. If you want the image you see to be truly accurate, you need to have your display calibrated.
Every display that was used to make the video you are watching was calibrated to the same industry standard along the way. So it only makes sense that I you want to see what the director truly intended for you to see, that you would calibrate your TV to that same standard!
Why aren't all TVs simply pre-calibrated to this industry standard, you might ask? Because the image that reaches your eyes is also dependent on the ambient light in the room. The THX picture mode actually IS pre-calibrated, but only for a pitch black room. THX can't anticipate what the lighting will be like in your room, but pitch black is the same anywhere
So if your room is pitch black, the THX mode is already calibrated.
If you have ANY ambient light though, then you need to recalibrate. The Panasonic VT30 plasmas already have pretty accurate color and greyscale if you put them in the THX or Professional 1 or 2 picture modes. All you really need to do in those modes is adjust the Brightness and Contrast settings so that you see all the detail in the deep blacks and peak whites that you're supposed to. You can easily do this for free with any THX Blu-ray or DVD. Simply go into the disc menu and look for the THX Optimizer. That will run you through some easy setup test patterns to dial in your picture fairly well.
If you want "perfection", you cannot do it by eye. You need a measurement device and some software. And that'll run you several hundred dollars at least. For a single display, the more cost effective route is to simply hire a professional calibrator. He will bring some very expensive an accurate measurement equipment and truly calibrate your TV to the industry standards. For most people though, this is overkill. Since the VT30 already has some picture modes that are pretty close out of the box, a simple user setup with the THX Optimizer will get you "close enough" to be entirely satisfactory to most people