This could not normally be done in a single turn
Both of these abilities use an Immediate action
Resistance (Su): As an immediate action, an elan can spent 1 power point to gain a +4 racial bonus on saving throws until the beginning of his next turn.
Manifesting Empty Mind also takes 1 immediate action.
When an Immediate action is used on your turn, it takes your Swift action as well
Using an immediate action on your turn is the same as using a swift action and counts as your swift action for that turn.. Since a turn only has one Swift action, this makes the combination impossible.
However, there are some ways to work around this
"Once per day as a move action, the wearer can take an additional swift action. This swift action can’t be used to cast a spell or spell-like ability."
Since Resistance is a Supernatural ability (Su) and not a Spell-Like-Ability (Sp), it could be activated using the extra swift action.
Empty Mind is a typeless bonus, and Resistance is a racial bonus, so the +4 and +2 do stack.
Use your next turn's Swift action
If you really need to benefit right away, you could spend your Swift action this turn to activate one of the abilities, and then, at the very start of the next person's turn, you could activate the other ability as an Immediate action. This will cost your next turn's Swift action, but it will give you the +6 before any attack affects you.