Well, LP, my thumb is positively black so take any advice I give with a grain of salt.
I too have the rolled leaf issue on my tomatoes but, I too, have no idea why.
I love clover and don't mind the dandies either but to keep the bees happily in their place (i.e. not in my lawn) I planted "bee balm" in a big patch where I don't wander (and out of the fenced yard) so the bees go there and leave us alone. So far so good, bees seem to REALLY like their balm.
Vinegar is good for weeds but I find you have to use a fair bit and it kills the grass too. Overseeding with grass seed sometimes help to crowd out the weeds. I go for keeping dandies and clover and I just cut more often and take the tops off before the flowers open, keeps them from spreading, or so I like to think.
Morning glories... I think 14+ took care of you there
Lilacs... new trees need lots of water, so don't be stingy there. Powdery mildew is really common and I think i've heard the same that it's worse if the trees are crowded, since your trees are new I doubt that's the issue but, they may have come from the nursery with the spores already on them. Maybe go back to where you got the trees from (if you bought them, I suppose you might have transplanted them from somewhere) and ask them what you can do.