Don't bother with either. Just get some small pots or cups and a bag of seed sowing medium and take it from there. Some seeds can be sown direct in the garden but since you don't say which seeds you have we can't tell you which ones.

If the hydro setup isnt being used then i dont see why you shouldnt use it to get a jump on the season..There`s no problem going from hydro to soil but it may take a several days for the plants to convert the hydro roots into soil roots. If you use hydro outdoors you wouldnt need to worry about it ;)