Can you make an attack using a spiked gauntlet while wielding a 1-handed weapon and a shield? If so, what are the penalties, if any?
Yes. Whatever penalties would normally apply.
If you're using a spiked gauntlet on an arm wielding a buckler, you have the same penalties as if you were wielding any other weapon (-1 attack, lose shield AC).
If you're using a spiked gauntlet that's holding a sword, there are no penalties for holding an object.
Can you deliver a spell touch attack while wearing spiked gauntlets? What about while wearing something like Gloves of Dexterity?
Ask your GM.
Some GMs will say anything discharges a touch spell, including gloves, rings, gauntlets, rain, dust, etc.
Other more reasonable GMs will say of course you can ignore the equipment you're wearing, otherwise all those clerics that wear armor that came with gauntlets are going to be pretty unhappy when they keep healing their gloves instead of their friends.
A magical gauntlet certainly wouldn't aid in your touch attack, though.