I shouldn't answer this since I'm way too new at soap making but I believe it depends on the characterisitics of the oil. If you google soapmaking oil properties or something similar you can find a ton info on pretty much any oils and they say around what % to use, of course always put your combo in the soap calc the one the glas provided on the site here
http://www.soapcalc.net/calc/SoapCalcWP.asp will tell you the properties of the individual oil and also the whole recipe. All the oils you said would be great addition I think. You can use your Coconut at 30% as well as palm but look at the spreadsheet and determine the rest out as you want. See what is most important do you want a hard bar, bubbles etc. Look at the numbers on side to see where they fall. Just make sure certain oils in certain ranges its something about the aount of staurated fat and other properties I think Palm Oil, Coconut oil, castor, avocado, and Hemp seed are recommended to be 20-30% of recipe then sunflower, safflower, hazelnut, cottonseed, calendula,kukui nut and others like taht are 10-20%. Lard can be 70% Olive Oil up to 100%, Shortening 50% but these are just numbers I pulled off a few blogs and they just give me a ballpark idea of what would work. That soap calc is a dream and I just look at the oils I have making sure I have few base oils I like to call them the ones that will put constistency in the bar then look at the properties on it till I see what I want. But again I'm really new. I've only made 5 batches of soap and though each made a good bar none are pretty. I just bought some fragrances and micas to spice it up a bit Yeah=) and BB does rock. But I do it for the house and family and as a hobby not for profit maye if my soaps ever get really pretty like some you gals and I put more time into it=)