I would say this constitutes pretty clear evidence of this being an alt account. I don't think any flags or ratings are appropriate at this stage. I think it would be appropriate to inform the managers of any campaigns he is involved in. If he is violating the terms of those campaigns, then a rating or a flag may be appropriate. I would like to hear the manager(s) comments on the matter.
They are both managers. I would be more curious to see if they accepted each other in campaigns managed by either.
Just a side note, I asked Little Mouse on telegram if they was alts of each other and was told no. Maybe telling the truth, maybe not. Can't really say for now.