Under strata title act, JMB/MC has no right to screen/choose tenant on behalf on owner,
but JMB/MC has the right to request tenant profile from the owner, just like JMB/MC has the list of all owners profile for the entire building.

This is something JMB/MC can work on.

Technically, JMB/MC has right to request those info as a list who are staying in their managed condo/property, so that in any disastrous event happened (building collapse/fire etc), they have info to look to assist for rescue effort, potential list of victim etc.

A lot of stratified property has problem of owner to pay up on time, or some even refuse to pay the maintenance fee, some even beat up security when their car being clamped due to parking in not designated lot.
Lack of cooperation may be the key problem for enforcement.
Yet, it is a SOP to get those info, and actually quite important JMB/MC to have those info.

Fyi
JMB/MC has the right to block common facilities access if owner/tenant breach house rules, but no right to block access to individual parcel unit.

Strata title act say none on this issue, hence the strata title act does not empower JMB/MC on any matter related to individual parcel apart from common property related and house rules on common facilities/surrounding.
Or in other word, the unit is owned by the unit parcel, he/she can sell, rent to anyone.

JMB/MC only can act on what have been empowered to them based on the act, eg
Collect maintenance fee, taking care of common facilities, fire insurance, impose house rules etc.
That is why even the unit owner defaulting the maintenance fee, JMB/MC cannot stop the owner to access to his/her unit.

The act doesn't say any sale/rent needs to take consent from JMB/MC.

Unless the property is under similar to restricted leasehold property type whereby there is leasehold agreement clearly stated any sale/rent of such property may require consent from the lessor.

My elementary understanding.
I think the limitation of by-law has been posted aurora97, in the earlier page. No2.
aka by-law cannot contradict with prescribed law.

If JMB/MC can set a by-law to have blanket limitation of certain nationalities even the tenant who is legally long stay here and has enter a proper tenancy agreement, then I would propose JMB/MC to set a by-law of a water and electricity cut or even rent limitation for unit that defaulting their maintenance fee.
This can be more effective to tackle defaulting problem then. But as far as I know, this kind of by-law is not allowed.

The issue is a bit different with bnb/homestay, that JMB/MC can use security reason to screen/block entry unknown tenant who has no proper tenancy agreement.