Q: I deleted a large number of contacts on one iphone when i got a new one. icloud must have automatically synced to the old one, then synced my new one to that, thus deleting many contacts. can i restore them?

When a device that is connected to an icloud account has it's contacts deleted, the same contacts at icloud.com are also deleted and then the changes propagate to other computers and devices also connected to the same icloud account.   In other words, the contacts are deleted everywhere.  Also, any iOS backup to icloud does not include contacts or any of the other Apple data, like calendars, reminders, etc.  The only way you can get that data back is if it was on a computer which has been frequently backed up.  You restore the data from the backup.  (This reference to "backup" is a local backup, it has nothing to do with icloud.)