I would check the base of the trunk to make sure they haven't already been damaged. Any bark rubbed away and I wouldn't keep them.
I can see what Verdun means as well. What sort of garden are you going to make? Will the trees be an asset or a nuisance?
Plant them, they may do OK and flower next year.
Don't keep them til autumn. Bin them if they'll take up too much space in your garden.
Fritillaria imperialis, crown imperials. I like to sniff the bulbs.
and Phuopsis stylosa, the smell of the foliage, similar type of smell.
and honeysuckle, sarcococca, daphne,
lots of stuff but not philadelphus or privet
Haphazard is fine
If it's only last night they should be fine,
what are the seeds? some are fussier than others
Warming up by the end of the week I think, things will move quickly then.
Different soil, different grass, more/less shade?
How long were they submerged, is it too late to drain them out?
Something like diesel would stop things growing and I don't know how long it hangs about. Some fresh soil and something shallow rooted might do it. There are bits of my garden where things don't grow, it was used as a dump for years.