Hey TedL,
HATEnFATE pretty much has it down. When it comes to idlers, I hate to use an absolute like NEVER. Because those parts fit so many of out Toyota's and Lexus' that they are around. Since I am not a High volumne store, I don't have the need to stock them like say and higher volumne store does. It really comes down to a percentage game. Again, if I am doing a belt, the small percentage of the time that needs Idlers, compounded with the number of times I need them, does not warrant me to stock them.
Other than a warranty and safety issue, which safety I belive is mandated by a minimum of 10 years by the feds to keep, the other items are again based on supply and demand and percentages. So many cars = % of opportunity divided by how many will remain, etc. Believe me, there is a whole section dedicated to numbers for these things. Again, it is the absolute word "all" that we have to get around.
As far as coolant, I have not come across anything official regarding the mixing of Pink and Red coolant. On this, I play it safe, what came out goes in. That doesn't mean the statement of upgrading or mixing isn't a possibility, it just means that I am a bit more conservative than most.
What I do disagree with HATEnFATE is the fact that when doing a T/belt, we do the belt, drive belts, water pump, seals, and coolant. It is a precautionary thing. I do agree with HATEnFATE on the fact that each dealer does do things differently, and if their shop does water pumps as needed, so be it. I'd hate to have to tell a customer that after I charged them X amount of dollars that it will now be an extra $ for a water pump we could have done with the belt. But that is me. I am not, by all means, second guessing HATEnFATE, I am just pleasantly disagreeing with him.
If the idlers are done as a common practice at a dealer, I will agree with HATEnFATE, I think that that dealer is unneccasarily over charging for something that is not absolutely needed as a precaution. If it is needed, I never have a problem telling someonel. But I think you know my position on the Idlers, If I am not mistaken, didn't I tell you that I didn't think you would need them, or was that someone else in that post? Not sure, but I don't rubber stamp the idlers, they need to be inspected at the time of the job.
TedL and others, I hope I and HATEnFATE, have answered your questions. If not, please don't anyone ever hestitate to contact me via a post, email, PM, phone call, anyway you feel comfortable with.