AFAIK by 1945 unless in an area of total air control (extremely rare) they weren't used during the day, just as night bombers.
As to the Schliesen:
It hit a British air dropped naval mine but didn't sink.
The Lutzow was hit by bombs, but not sunk:
Both sides were scuttled by crew at the end of the war.
Theoretically, but the problem is getting those units into action. Constraining port and territory held would be a major obstacle to deploying and rotating units. Couple that with the storm that smashed the Mulberry harbors and things get tough.
The weather was always an unknown factor. Storms in the English Channel have always been violent, with the wind whipping the waves in the confined area between Normandy and England. The great storm of June 19-20 succeeded in doing what the Germans had not been able to do - destroy the great
www.history.navy.mil
If some of the beaches fail then the constrained logistics situation caused by the storms would severely undercut the sustainability of the bridgehead. Which brings us to my point here: it didn't take much change to bring about significant alterations to major campaigns, which could have massive strategic consequences. That said Overlord being trapped at the beaches still helps tie down German forces and allows for Dragoon to be carried out in Southern France, which might break the deadlock in the Allies' favor.
Less than half of those were worth a damn or had sufficient equipment. Most of the ones over the 12th SS in numbering had insufficient manpower or equipment in 1944. It was really only 1-12 that were decently equipped and even then that was highly contextual with some not really being notable like the 4th SS division, which was intended as a police/security unit.
Also remember many of them were foreign units which would not fight in a civil war if push came to shove. Also remember at their very peak the SS had about 800,000 men (not in July 1944 and mostly at the fornt), while the replacement army alone (not at the front) had over 1 million men.
It failed IOTL. Hitler lived and was able to broadcast quickly after the attempt before the coupists got their plot rolling. In that case due to wanting to avoid a civil war most civilians just waited to see what the outcome would be. The reality is most people in a period of conflict don't want to get involved even if they support one side or the other since they aren't fighters. By 1944 the average German was either female, a child, or old, so had zero ability to decide the coup one way or the other. The younger men with guns were the ones who decided and most had no idea what was going on until it was already over.