Probably not alive. You don't see veins when they are ready to hatch. The egg looks completely dark and if you watch real close you can see movement and sometime see there little beak move.
I believe the float test only looks for development of the air cell size; you may want to try the candling method instead.
Did you see the water wiggle ??? That would indicate that the chick is alive. I personally don't do the float test; I'm concerned that the pores of the egg shell will fill with water and interfere with the passage of oxygen and waste gases. IMO the float test could drown the chick. JMO.
Sometimes chicks do hatch late; the veins can be visible in areas of the egg where the light can reach. You may want to give them a few days more. I have read of hatches that did take much longer than usual; however, this is unusual. Waiting a few more days is ok--you've come this far. GL
I would wait 48 more hours/ I have a trusted friend who has had hatches go to day 26...sometimes diff things make them develope slower...lower temps being one...will be hoping and praying you get a pip tonight!