BS!!! You don't need to do other belts. If your exterior belts are fine, LEAVE THEM! That's just wasting money.
As for the tensioner, THE SAME!!!! Don't fix it if it isn't broken!!!!! Tensioners aren't a wear part, so you shouldn't be expecting it to go at any time. They are a more rare part to break.
Gaskets and seals, THE SAME! Don't fix stuff that doesn't need fixing. If you fix any gasket before fluid is dripping on your garage floor, your wasting you money. If you see just a little residue, that's fine. You have thousands of miles to go before it is dripping. Your just wasting your money if you fix it that early.
Water pump you do with the timing belt, because you need to take the water pump off to do the timing belt. So your basically saving the labor charge of taking the water pump off again. HOWEVER! Timing belt is to be done at every 60,000 mile mark, not 90,000. So if you haven't done it yet, your really pushing it. And if you have had it done once previously, don't spend the money doing it now.
This is all stuff you would hear from techs in a shop. If they tell you anything different, it's a sleazy shop that is just trying to sell you on stuff. My shop wouldn't dare push any of those items on people that didn't need them.
'88 Toyota MR2 N/A - Sold
'99 Miata Sport - Sold
'85 Corolla GT-S - Sold
'02 MR2 Spyder - C-Stock car