I have noticed a few of the warlock spells in particular that are missing from the compendium to drag and drop onto the OGL sheet (Arms of Hadar and Hunger of Hadar were noticed for instance). Is there a way to either get these into the compendium or not so much at the moment? As of right now I just typed em in as needed which isn't a big deal. The other part that I had a question about was if it was possible to drag and drop feats/racial features/other character related stuff to the feats and traits areas as well as proficiencies for like tools and languages? Since the sheet updated everything with these were erased so I just wanted to try to make it easier on my players to get everything back on track.
The compendium can only contain content present in the srd for a given system. Those missing spells are not part of the srd. Note that the srd is not the entire PHB. For your second question,I haven't used the new sheet,so don't have any insight for you there, sorry.
As far as I can tell you can't drag and drop racial traits and feats (other than grappler) into your character sheet, you have to fill them in manually. As for getting back the stuff that you and your players had already written, if on a character sheet you click the cog in the top right there should be a general options section on the right. If under Features and traits you change compendium compatible to simple, you *should* get the original notes for that section of the sheet.