(In second-last paragraph on Kroger, removes incorrect reference to negative impact of weather)
* Factory orders, durable goods data due
* Staples, Costco shares down after results; Kroger up
* Futures up: Dow 25 pts, S&P 3 pts, Nasdaq 3 pts
NEW YORK, March 6 (Reuters) - U.S. stocks were set to edge higher at the open on Thursday following upbeat labor market data, while developments in the Ukrainian crisis kept traders on edge.
* Crimea's parliament voted on Thursday to join Russia and its Moscow-backed government set a referendum for March 16 on the decision, in a dramatic escalation of the crisis between Russia and the West over the Ukrainian Black Sea peninsula.
* Moscow stocks fell 2.2 percent and the ruble weakened 0.7 percent versus the U.S. dollar after the Crimean vote. A U.S.-traded Russian ETF fell 2.4 percent in light premarket trading.
* Weekly applications for U.S. unemployment insurance fell to 323,000, the lowest in three months, a sign of strength in a labor market that has been hobbled by severe weather. Sales and orders for long-lasting items are due at 10:00 a.m. EST (1500 GMT).
* S&P 500 e-mini futures rose 3 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures rose 25 points and Nasdaq 100 futures added 3 points.
* Costco shares fell 2.7 percent in premarket trading after the warehouse club operator's quarterly profit fell 15 percent, missing analysts' estimates.
* Shares of Staples dropped 12.7 percent in premarket trading after the largest U.S. office supplies retailer forecast a fall in sales and said it would close up to 225 stores in North America by 2015.
* Kroger Co, the biggest U.S. supermarket operator, reported a drop in quarterly profit. Still, its shares rose 3 percent in premarket trading.
* On Wednesday, major U.S. equity indexes were little changed, with the S&P 500 down just 0.1 point from its record close Tuesday. (Editing by Bernadette Baum)