Can you pick up two items in one action if they are in the same space?
Yes, see Trade on page 18 of the RR.
An investigator can perform the trade action to allow himself and each
other investigator in his space to give any number of his possessions to
another investigator in his space, pick up any number of possessions
in his space, or drop any number of possessions in his space.
- These effects can be resolved any number of times and in any order.
This also means that if Investigator A uses a Trade action, then Investigators B and C can trade between themselves or they can pick up objects.
The reason is that if B wanted to give something to C, then the rules allow B to trade with A and then A trade with C.
If B wanted to pick something up during A's action, then what happens is A picks it up and then trades it with B.