I don't actually know that much
But anyway, concerning the fat loss and muscle gain not being possible except for during newbie gains, I don't happen to agree with that one. If it is possible during newbie gains then it stands to reason, logically, that it is possible and why people put a time limit on it baffles me; besides I have read of lifters doing exactly that even though they are not new to the game...and it's even logged in my journal that I did the same thing after being at weight training for some time; I lost 1.5 lbs fat and gained 1.5 lbs muscle simultaneously and Doug did the calculation, so it is possible...never let someone tell you it isn't. If it is said that a newbie can do it, that means it is possible, period! To then say it is not possible under all other circumstances is to negate that it is possible at all.
Where muscles become denser, don't forget that strength training continually renews the density and it does not necessarily stand to reason that a muscle must at some time become bigger, although I do agree that there has to be some increase in muscle size due to its use...but I am unable to explain further on this point...no knowlegde as such, one of the other members might be able to explain; however, next week I intend to start a strength based routine, so I'll do some measurements and let you know in about a month, that should be long enough to notice changes, with any luck.
Hope that has helped a bit.