Tires: replacing Eagle GT II P215 65R15 95T, bf goodrich, eagle gt

Question
I want to replace the left rear Eagle GT II tire on my '91 Toyota Previa.  I was thinking about getting one Michelin of the same size (since Goodyear was out of stock) but the salesperson said that the Michelin was a 95S and I should get a 95T so I should get the BF Goodrich 95S of the same size.  
I understand that ideally it is good to get all four tires of the same brand, model and size but what should I consider if I do get only one tire?
Should I rotate that new tire to the front so that I have two of the same on the rear axle?  thanks.  Leighton Loo

Answer
Leighton,

As you stated, ideally all 4 tires should be the same size / type/ state of wear.

However, if you can't do that, you should have the tires "paired" on an axle.

If you can't do that, then the tire ought to be the same type as the other 3.  That means it ought to be a T speed rated.

And it should be mounted on the rear.