If California brings an anti-Prop. 8, measure before the voters, depending on the outcome of their Supreme Court’s ruling, that will make three (or is it four?) times the people there will have voted on the issue. How many times can they do that?

I suppose they can keep going back and forth forever.
However, trends seem to be showing that the population is becoming more supportive of same-sex marraige over time. So once it is relegalized in CA (in, I’m guessing either 2010 or 2012), I think it’s going to stay legal. I doubt that opponents are going to be able to raise the money to try and change it again if they don’t think they can win.

As to your other question, I think religious protections are a legitimate concern. But there are two basic mindsets: the one that says no to gay marriage, period, while realizing that affirming basic rights for domestic partners is necessary (some will even say no to that) and the one that sees it as inevitable but wants to assure religions freedom and conscience are protected for objectors.

I think you’re probably right.
One thing that jumps out at me is this: those states that legalized marriage by statute are those that provided religious protections. Those that were changed by courts only answered the question before the court.
I think at this point it is probably likely that more courts will find that marriage laws that exclude gay couples do so in violation of the “equal protections” clauses of their own state constitutions.
It may well be to the interest of religious activists to make a compromise whereby they will support marriage laws that offer religious protections in states without constitutional amendments defining marriage. They may be able to broker a pretty good deal. Otherwise it may be just a matter of time before courts make that decision for them and give them nothing.
I’m not sure how realistic that is, but it might be worth consideration on the part of conservatives and religious activists.

Thus, a state government does not violate the U.S. Constitution if it insists that all adoption agencies – even those operated by religious organizations – must be willing to place children with same-sex couples in order to receive state funding.

Yes, a very good point. Not sure how many gov’t-funded agencies will decide to close their doors and not go it alone, but they certainly could take that option.
As to this:

In fact, from what I’ve heard, if the CA Supreme Court does not overturn Prop 8 on Tuesday, those who are crafting the language for the initiative for the voters to reverse Prop 8 will be including religious protections.

It leaves me wondering how many states are going to jump on the referendum roller-coaster on the gay marriage issue. If California brings an anti-Prop. 8, measure before the voters, depending on the outcome of their Supreme Court’s ruling, that will make three (or is it four?) times the people there will have voted on the issue. How many times can they do that?
As to your other question, I think religious protections are a legitimate concern. But there are two basic mindsets: the one that says no to gay marriage, period, while realizing that affirming basic rights for domestic partners is necessary (some will even say no to that) and the one that sees it as inevitable but wants to assure religions freedom and conscience are protected for objectors.