1 - In principle, try to maintain a negotiation with China for the distribution of markets and places to invest in in Africa, with certain permissions to be able to operate in another's market. A bad peace is always better than a good war.
If they refuse, use Russian influence in the area to gradually close and deny Chinese access to certain important markets (not all) but allowing them to operate up to a certain volume, no more.
If they continue to refuse, try to deny China any influence, relegating it to only being able to maintain minor investments and markets.
2 - Given that it will be difficult for them to renounce their positions, and give up possible gains, the only thing I can think of is for the International Courts to set the limits or try to establish an arbitration court that determines the limits to try to buy time. While negotiating with the leaders, tempting them with the possibility that a shared exploitation will bring them profits now (sweetening it with promises of investment and if necessary some small gift), while continuing to fight over who gets which area, can make obtain fewer and later profits.
3 - First of all, putting its founder as an example of what the Russian people may be capable of achieving, highlighting the state it was in less than 20 years ago and how much it has prospered, and offering it political recognition , academics...
Secondly, offer you an agreement for total or partial exemption from some fees, investment facilities, in exchange for investing in Russian entrepreneurs and helping them to prosper, and in exchange for purchasing (in a hidden way) on behalf of the State partially or entirely foreign companies in sectors important for the Russian economy