Are there general rules for activation of this kind of abilities using Mairsil?
Are there some specific rules for activation of ability of Callous Oppressor? He need for a creature type but you can use ability to all other creatures type.
Mairsil's last ability refers to all activated abilities of cards in exile that are owned by Mairsil's controller (C.R. 109.5) and have cage counters on them, even those with a stated choice. However, for all three cards you mention, the ability gained this way will not refer to any choice, so that choice is undefined (C.R. 607.5a; C.R. 607.5 applies only if an object acquires "a pair of linked abilities as part of the same effect", which for Mairsil will be true only if both abilities are activated abilities, however [an example is Sisters of Stone Death; review C.R. 607.1]). For Sarpadian Empires, Vol. VII and Belbe's Portal, those abilities can still be activated, but won't do anything (C.R. 607.5). Callous Oppressor, on the other hand, is a very particular case: its last ability refers to "target creature that isn't of the chosen type"; we have here a targeting restriction that refers to an undefined choice. If such a restriction is deemed such that it can't be fulfilled, that ability can't be activated. On the other hand, if such a targeting restriction is deemed such that it can be ignored (so that it becomes "target creature"), then the ability can target any creature (since it won't be of an undefined type).
EDIT (Apr. 17, 2020): Edited to conform to rule update with Ikoria: Lair of Behemoths.
Are there general rules for activation of this kind of abilities using Mairsil?
Are there some specific rules for activation of ability of Callous Oppressor? He need for a creature type but you can use ability to all other creatures type.
Thanks in advance.
WUBDakkon, a Tribute
BChainer, the demonlord!
RWAurelia
WBKarlov of the Ghost Council
EDIT (Apr. 17, 2020): Edited to conform to rule update with Ikoria: Lair of Behemoths.