Apartment/Room Rental/Sharehouse and tenant rights (condo, house)

[brighthope]

Hi,
I recently made some friends from foreign countries/of temporary residents through my social activities. Most of them are here with working holiday visas and only stay here for 1 year. So they don't usually rent an apartment in a rental building or condo, but find a sharehouse or a basement apartment, typically with the owner living in the same property.

Anyway, what I found is that most of the owners impose some strict or sometimes strange (house) rules. The most common ones include, but not limited to "no visitors or guests" "no cooking certain foods" etc. The most ridiculous one I have heard is "Don't put ANY paper (including toilet paper) in the toilet". Another thing I noticed is that many landlords come into the tenants' living spaces without notice, although some of them come in to clean (and sometimes it is part of the agreement). Also, I know of some cases in which owners kicked the tenants out for some trivial reasons without notice which would be required in the normal landlord tenant relationship.

Anyway, it seems like what I mentioned above is quite commonplace among them and I was flabbergasted and I thought the owner should not be allowed to act like that or impose these rules.But again, they are renting out some spaces, not the whole property. In a way, it's like living with a roommate who happens to be the owner. Roommates have house rules. They share things. So if I think that way it does not seem to be that strange all of a sudden.But I wonder where the cut-off line is.

Are they(owners/landlords) technically allowed to rent out spaces this way?
Do they not have to follow certain rules/the landlord tenant act?

Anyway, I just want to know the general rules because some of my friends are having trouble with their landlords.

Thanks!