The bonuses are typed, so no they do not stack, nor do they stack with any other bonuses of the same type
for example the AC one is an insight bonus.
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Bonuses of the same type do not typically stack. Dodge bonuses and some circumstance bonuses are the only bonuses which do stack.
Because the Dusty Rose Prism provides an insight bonus which does not stack, you'll only get +1 no matter how many you wear. The Deep Red Sphere provides a +2 enhancement bonus to Str. Enhancement bonuses also don't stack so a second Deep Red Sphere would not provide a bonus, nor would a belt of Dex.
Dig?
Same as above but do remember that some specific abilities do stack -- but only because they specifically state that they do.
Same as above but do remember that some specific abilities do stack -- but only because they specifically state that they do.
Also note that magic items never grant these kinds of bonuses. If you could have, say, an ioun stone that grants you a +1 dodge bonus to AC, you could just get 10 of these and get +10 to AC. And 10 is just an arbitrary number - it could also be 100, if you have enough resources.
Since you always pay the same for such items (the "dodge ioun stone" would always cost, say 10000 gil, no matter how many you already have), the cost for higher bonuses would now be linear, instead of exponential as they usually are (+1 deflection 2000, +2 8000, +3 18000 - since the formula is bonus squared * 2000)
That means that you either get higher bonuses for a lot less than they should go for or that you'd have to make them cost so much that you can't scrounge up a ridiculous bonus unless you have a lot more money than the game is set up for - and that would mean that a single, simple +1 item would be way too expensive to be feasible.