If you just wanted confirmation. As of now, basically all of the major known LI's are.
As you can see, the first five volumes are dedicated to the first five major love interests, but not in order of acquisition. Volume 5 is the Saintess who is youngest, and who grew interested first (out of those five). Then it goes volume 1's Captain, volume 4's Karla, volume 2's Madoka, and then the final member is volume 3's Sister (nun). None of those 5 are sexually active, and in most cases are either too young or have issues preventing it. Karla has her very understandable reason for aversion, the Saintess is both too young and sheltered by the Church, the Nun just got done with her training, Madoka wasn't really seen as a woman by her hometown, and the Captain was dealing with not using her half-succubus powers as well.
The other LI I know of probably is a virgin, because she's been focused on Ruga since she started the academy a year under him. We meet her in the next arc. Well, there is technically another, but . . . you'll understand why I didn't count them.
The WN doesn't really go into the rank and file of the 5th squad as of where I stopped reading for now, but assuming the words from the main antagonist of the last arc/volume is true? Yes, members of the 5th have been Sexually Assaulted and raped before joining, thanks to bandits and the ilk prior to becoming knights. It hasn't been brought up again, so no idea how widespread that was.