Windows can't read from, and definitely can't boot out of an LVM partition. However, if you put Windows in a normal partition and your Linux in LVM they will happily ignore each other and work just fine (don't forget to put /boot on a normal partition too).
I've had this setup for years without issue. I don't boot Windows often (I think it's been a year since I touched it) but last time I checked it worked fine, and it has never messed up my Linux install at all.
As for whether LVM is safe to use, you should always have backups but I've safely resized LVM volumes several times without issue. If the FS supports it you can even do it online (xfs and jfs do); add a physical volume, grow the LV, and then grow the filesystem while it's still mounted and in use.