For the Fuji CA II 8x10 paper I ordered...
Can I process it Kodak RA-RT chemistry? At room temp?
Not sure about Fuji CA II, but the variant of CA I'm using works absolutely perfectly with Kodak RA-RT, without starter, at room temp (23 deg C), 2 min 30 sec or so.
Can I tray develop with consistent results?
Yes.
Do I need to replenish chemistry after each print?
No. I have done around hundred or so 8x10" prints with one liter of developer. I think it works like B/W developer, you start losing contrast and maximum blacks and can counteract that for some time by adding dev time, but at some point you need to replace the developer. I'm saying "I think" because I don't remember ever seeing this, I just have tossed it at some point because I have decided that the blix has exceeded its useful life and I have equal amounts of developer and blix anyway...
Is it REALLY ok to use a Kodak Amber #13 safelight, or is just PB best?
At REALLY low light levels, yes. I use yellow leds (not greenish-yellow!, not orange), without filters. If I added #13 filtration, I would probably be able to crank up the light level a bit, but I haven't found any good deal on #13 safelight filter. Please note this is a different filter from B&W amber safelight.
Anyway, the level of safelight allowed is such that you cannot see ANYTHING when you first turn off your lights, but after 10 minutes of your eyes adjusting, you can see surprisingly well. You can (barely) see the edges of the white paper against black objects, you can see where the developer tray sits...
I'm using a much higher level of yellow safelight near the developer tray which I turn on when the developer time is over, to transfer the print to stop. At this point, much higher level of illumination is OK.
Is there standard enlarger color settings to start with or one specific to Kodak Portra 400?
Depends on the enlarger. You can try to start with the values printed on the paper box. It can be typically around 50M50Y or so. On the Fujimoto enlarger I'm using, it is more like 50M100Y. The scales can differ quite a bit between enlargers.
After you have nailed it down once for images shot at a right color temperature for that film (that is, natural daylight), the filtration will be very close for further prints too, not only for Portra 400, but for other color negatives too!
Is a stop bath needed? Is a water stop ok if so?
It is highly recommended in tray processing, otherwise, you have a risk of some streaking. Use acetic acid at 2%. I use it at about 1% to reduce smell, but change it much more frequently, about after every 10 prints.
I also add a very quick water dip after the acid stop. Probably not necessary, but helps maintain the pH of the blix. I just happen to have a good spot on the table for this bath.
Does the color balance shift considerably depending on exposure?
Practically not at all. The products are very linear.
Will dodging and burning give different color casts to different parts of the print?
No, see reason above.
Anyway, thanks in advance!! There doesn't seem to be as much info on color printing as there is BW printing.
I agree. But it's really simple and fun because the products are well engineered!