Yeast Problem

Not exactly sure what you are asking.
If you don't have an OG that's fine. You can still get the FG. You just will not be able to calculate ABV. But you will know, roughly, if the yeast have converted wort to beer, and you can track if it is still working.

Repitch if you think necessary. It will not hurt a thing.
Cheers

 

I concur with @billandsuz and I'll suggest that you repitch the same yeast you initially did. That yeast you put in is not dead, and it will eventually start up. Fermenting with dual yeast strains isn't really something for beginners so just go with what you've got. Then, if you want to, you can reuse it.

 

You didn't mention the fermentation temp and what yeast you used, but some yeasts will work at a wide range of temps. Can you see inside your fermenter to determine if there is a ring of dried foam on the fermenter wall around the edge of the liquid? Sometimes fermentation happens so quickly that you don't see it happen, and it's possible that your beer is done. How's it smell?

 

The safest way to tell if fermentation is complete is time. If you have a hydrometer on the way, I'd leave your beer alone until you get it and then take a couple of readings a couple days apart. If your second reading is the same as the first, and both are close to your recipe's predicted number, your beer is done. It's also had enough extra time to clean up behind itself, so proceed to packaging.

Enjoy your beer. Let us know how it is.

 

You did not reference what type you used or what temp you are fermenting at. I can not give advice with only part of the story. Take care!

 

I would follow the rule of KISS. Just bring up the temp. and it should kick off. Imperial flagship is basically "Chico" which I've quite often fermented warm without issue. I'd routinely run Chico, WLP001, US-05, S-04, and all kinds of Belgians at 74˚F across several breweries. I wouldn't trust going up to 80 except with certain Belgian strains.