Can I delete photos on my iPad to free up space IF I am backing everything up in iCloud?h

Be careful to fully understand your iPad settings - and impact of these settings to the consequences of deleting photos or data:

Settings > [Your Name / AppleID] > iCloud > Photos > iCloud Photos - select from ON | OFF

If you have enabled Photos in iCloud, your Photos are automatically synchronised with iCloud. As photos are synchronised with iCloud, the photos will not be included within an iCloud backup. Deletion of photos from your iPad will also delete the photo from iCloud.

If instead you have not enabled Photos in iCloud, your photos are included in your iCloud backup. Deletion of your locally stored Photos will only delete the photo from your iPad - however, the next backup cycle will also remove the corresponding photo from the iCloud backup.

If you need to archive your photos, protecting them from deletion, you’ll need to copy them to somewhere other than your iPad/iCloud Photo Library.