Goal of getting every character to Best Friends by G&G 2026

okay so I'm posting this now knowing I probably won't achieve it but I want to try to get every character to their best friend level by next December so I can acquire every Holiday Bear this year.

that includes Cogimyun and Usahana (both DLC)

I should note that I only recently got Wish me Mell, My Sweet Piano, Tophat, Big Challenges, Kiki and Lala, so they're still very low level compared to others, and I haven't even met Moppu yet.

what is the fastest way to complete this? I want to compile ingredients and materials to be able to give everyone a 3 or 2 heart gift every day for increasing the levels more quickly.