This always happens, unless you spread a fairly small mesh over the pond in autumn.All you can do is to scrape them out and the best time to do it is the autumn. Frogs do overwinter buried in the silt at the bottom of ponds so bear that in mind.

you can fish them out with a net but leave them on the side of the pond. this will allow any critters to crawl back into the water. I usually rummage through the leaves in a shallow tray of water, picking the leaves out by hand. they then go on the compost bin.

welcome to GoY too.

I would definitely remove the rotting vegetation. When you remove the dead leaves, be sure there aren't any frog eggs clinging to the bottom. Just put the eggs back in the pool. Green plants are fine, but the decaying leaves will change the PH of the water which may not be good for the frogs, especially since it's a closed system. Composting leaves consume a great deal of oxygen that the frogs need.

Maybe you can add some nice water lilies. They will add oxygen to the water for the baby frogs and they can hide from predators.

No danger of frogs eggs at this time of year. Any frogspawn will have hatched and be well grown by now and the frogs will be off and away elsewhere in the garden..adult frogs don't normally live in the pond over the summer though they may visit it occasionally.. But if you are lucky you may see some tiny baby newts. But do as Seaburn says and anything like that will crawl back into the water.As long as you have plenty of oxygenating water weed the balance should stay OK. The time to worry about oxygen is if the pond gets covered with ice, when any noxious gases are unable to escape unless you leave a hole in the ice.