Concerning foreign airplane use in Russia, I had a look at available data for the exisiting major Russian airlines.
Not just Aeroflot, but the three other airlines owned by Aeroflot (Aurora, Rossiya and Pobeda) have all only western aircrafts (including regional turboprops from bombardier, in the same class as the il-114)
Aeroflot currently operates 115 medium narrowbodies of the A320 family and 47 boeing 737.
It has 50 russian MC-21 in order.
In addition it operates 41 widebodies (airbus A330 and boeing 777), and has additional 22 boeing 787 in order.
The only russian aircrafts in operation with Aeroflot are 49 ssj-100 (with additional 100 in order)
Rossiya has currently 21 a319 (about 120 passenger each, could be probably substituted by the 100 passengers ssj100), 22 aircrafts between A320s and boeing737, and 19 widebodies (boeing 747 and 777, that could be replaced by il-96 400M).
Aurora operates 10 airbus a319 and 8 smaller bombardier turboprops.
Pobeda operates 30 boeing 737 and has additional 20 in orders. (I know that they are basically a russian "easyjet" and that they need tested aircrafts, but if the business case is not there yet it would be better to temporarily park the concept of expanding the operation of such low cost airline until the new russian mc21 have the necessary operability instead of ordering additional american aircrafts.
Concerning the other major airlines in Russia (non state owned)
S7(Siberian airlines), Russia's biggest domestic airline operates circa 80 medium range narrowbodies with additional 12 in order (all A320 family or boeing 737) + 17embraer 170 (the latter should be eventually replaced by ssj-75
Globus airlines (formerly owned by S7) operates 21 boeing 737 and has additional 10 in order.
Smartavia (previously nordavia and aeroflot nord), based in archangelsk, currently owned by "skyinvest" operates only american aircrafts, with 14 boeing 737 of various types.
Nordstar in Krasnoyask operates 7 boeing 737 and 4 ATR 42 turboprops
Nordwind Airline (based in Moscow) operates 17 narrowbodies (A320 and b737) and 11 widebodies (a330 and b777). Apparently it has 5 russian mc-21 in order.
Red Wings airline has currently a dozen A320, but it should substitute them with mc21starting from 2021.
Ural Airline (Yekaterinburg) operates 46 narrowbodies of the airbus A320 family and has 14 boeing 737 in order.
Utair Airline operates only western aircrafts: 15 atr 72 turboprops, 47 boeing 737 (with 30 new 737 in order to replace older 737 models) narrowbodies and 3 boeing 767 widebodies.
Yakutia airline has a mixed fleet with 6 old An-24 turboprops, 4 bombardier dash 8 turboprops, 7 boeing 737 narrowbodies (with 10 in order) and 4 sukhoi ssj100
Yamal airlines operates 11 a320 narrowbodies, 11 small bombardier Crj200 small jets (50 passengers) and 16 sukhoi ssj100.
There are probably way too many airlines anyway. In the soviet union times there was only aeroflot, and that helped also the aeronautical industry, that could better plan the production.
In addition, there should be some proper protection for the local aeronautical industry. That means only Russian aircrafts for state owned aircrafts, and for all the other airlines large import tarif (at least 15 %) for acquiring and operating (so also for maintenance contracts) foreign made aircrafts.
American, Canadian, or France/German airlines would not acquire Russian aircrafts anyway, so even if they close their market for russian aircrafts in response it is not a loss. All the other nations do not produce modern commercial aircrafts, so for them it wouldn't change anything.
As far as Brazil, they currently they import all of their widebodies and medium range narrowbodies. Brazil produces some modern regional jets and turboprops, but their largest commercial aircraft has the size of a streched ssj100 (E195-E2)
and I doubt they will buy il-114 or ssj100, since they are currently market leaders on these segments.
The Chinese civilian market would not be open to Russia anyway, except for the joint developed CRAIG 929. As soon as the comac 919 will be operational they will stop using airbus a320 and boeing 737 and there is no chance that they will buy some mc-21 (even if it is a much better aircraft than the c919).