Is it safe to take 75mg of wellbutrin, 10mg of celexa and 2mg of Abilify (aripiprazole) all at once?

Yes. It is safe to take those three medications together as long as the they were prescribed by the provider, and the provider who prescribed them is aware of the potential for interactions. As with any medications, if you experience side effects you should get in touch with the prescriber if they occur.
Depends. If these have been prescribed by your doctor, then yes, these are safe to take together. These are the smallest doses of these drugs, which is great to minimize side effects.