Cold frame contents

This is practically unnecessary at this point this year, but we are still getting nights in the 30's; the soil temperature is mid-50's, though.  I want to sow lettuce and greens and also start up some transplants for April.  This is the first year trying any of this, so do y'all think I can put all that stuff in the same cold frame--direct sow the greens and put my other seeds in little pots?  
The proposed spot is full sun, as is most of our yard.  The frame is 33"x77" if that's of any importance.  I sized it to the stationary half of a sliding door.

Using the cold frame ought to raise your soil temps to levels for successful germination of direct seeding within a day or so. Having the lettuce, greens and what not all in in the same cold frame isn't going to be any different than any other place, as long as they all fit. Be sure to monitor the air temps as well so you don't burn your seedlings.