It looks like he is merely rehashing what Alan Nixon claimed and reporting what was in the English papers said. So it is not another source for the rumour, it is essentially the Nixon rumour retold in French.
Probably because Aston Villa already spent circa £100m on attacking midfielders, Emi Buendía, Leon Bailey and Philippe Coutinho. That doesn't mean Gerrard wouldn't have liked Aribo, just they probably feel they've spent enough already.
I very much doubt it. That salary for Broja was signed with him in the Chelsea youth teams, where as Bazuna, Lavia and Bella-Kotchap have been signed by Saints to be 1st team players and their wages will likely reflect that and be significantly higher.
No, not even close. Some Saints fans underestimate just how much Saints are paying players. Saints have an annual wage bill of £113m, that isn't from paying mid range players £20k p/w.