Boar pairs are wonderful! Boars tend to mellow with age and become more affectionate and friendly as they age.
Boars do need more space though as they are more territorial. Two boars need a cage measuring 180x60cm.
They do scent mark more and they can smell a bit more but it’s not a case that they smell bad.
It can be advisable to only change half the bedding at a time as that can help reduce dominance and territorial behaviours as they will still recognise the cage as being their space. It can also help reduce the scent marking (they scent mark to mark territory so the more thoroughly you fully clean the more they will mark and the more it will smell)
Yes they can be neutered safely provided the vet is experienced, but a young piggy can’t be neutered until they are 4 months old (and then there is the six week post op wait to become infertile). Therefore if you were to want a male and female pair it would mean a young male could end up be alone for a long time before he could have a sow companion which is far from ideal.
As you are having trouble finding a young sow, then two boars living together do not need to be neutered. Neutering only prevents pregnancy, it does not change their behaviour at all.
However if both of them were to be neutered, if when one of them passed away, it would mean that they would be ready to be bonded with a new sow companion.
Boar pairs can only ever be a pair though - you cannot add to them. No other piggies can be added into the cage with a boar pair ad it will cause them to fight.
If you were still planning on taking a boar pair to school, then it is even more important that you reconsider that and don’t do it with a boar pair. Boar pairs are very territorial and any change in territory or anything that unsettled them can cause issues. They need to know their environment is theirs and is stable so ensuring it smells like them all the time Is a good idea.
A Closer Look At Pairs (Boars - Sows - Mixed)
A Comprehensive Guide to Guinea Pig Boars