If initiative is numerical, then it could just be whatever number the computer has determined.
Whether it's worked out each 'round' or if it's a static number determined at the start of combat.
Lowest or highest order, I think people will work it out when they see 14, 12, 11, 10, 10, 9, 8, 14, 12, 11,... (or counting up)
It's clear that 14 is the highest and the numbers wrap around when it hits 8 and goes back to 14. Assuming initiative is determined once at the start of combat, the 14, 12 and 11 will also have the same portrait.
Even if initiative is a number that counts down to when it's your turn. You could just have the number that the computer currently has assigned on the portraits.
eg: 0, 1, 2, 4, 7, 9
Knowing this information.... I would then request an option to add 1 (or whatever set number) to my current character's initiative. This way I could let 1 or 2 people ahead of me in the initiative queue (depending on the numbers and what we're allowed to add).
This would be really helpful when a character is blocking me. I could let them go first to move out and into cover, then move the blocked character. Currently the blocked character has to lost an entire turn.