Is it typical to use an uncertain affiliation within a paper? I am an international graduate student, recently-admitted to a Canadian university. My admission has been finalized and I am just within the visa processing to acquire required study permit.

Now, I am going to submit a proceeding paper and feel myself in a dilemma to determine my affiliation within that, appropriately. As a matter of fact, my preference has been focused on utilization of my position
in the new university, instead of my undergraduate affiliation. But one might, realistically, imagine the situation that I use my favorite affiliation for the target paper, but (for any reason) I will be rejected by Canadian embassy to acquire the study permit. In this case (I hate even thinking about it!), I not only lose that position, supposedly, but that applied affiliation onto the paper will, also, be invalid, actually.

Now, technically:


Is it ethical to do something like that in academia, or I must bite the bullet for stabilization of my expecting affiliation to be applicable,
formally?
What are the potential consequences for me and my paper, if above scenario would be happened?
No. There is no bullet to be bitten. Whenever you submit a paper, you just list your current institution as your home institution, no matter what you want to put here.

The affiliation on a paper has two purposes:


to allow others to contact you - nowadays it's mainly a disambiguation in case your name shows up multiple times on an internet search, but in former times, the institution information was necessary in order to send the author a letter or in order to call him/her;
to assign credit to the institution that supported you during your research.


The Canadian university did not do any of that (yet), so they should not be listed. Note that if you already started at your next institution when the final version of the paper is due, then it is entirely reasonable to update your affiliation then, just as you would update an e-mail address that expired. However, for reason number two from above, you would add a footnote stating that the work was carried out while you were still at your former institute/university.