That orb was a drawing mistake. Prior and after that moment, Madara was never shown with an orb when absorbing a Jutsu, except that instant whereas Nagato was always either himself or through Gakido Pain. So it's pretty obvious the orb in that scan was a mistake, as Kishimoto made drawing mistakes a lot. I'll point out examples:
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] Madara isn't shown with an orb when absorbing FRS. Compare that to the scan you posted for Pain.
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] Not shown with an orb when absorbing Jinton.
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] Not shown with an orb when absorbing Amatersu, and added with the fact he was blind, thus making your presumption of him using Preta Path invalid, if he could absorb Jutsu while blind.
I want to also add on few things:
1. Nagato has shown no limit when absorbing techniques. ET Madara's limit was FRS; if he was actually using Gakido, he would make no such statement.
2. Nagato could use Gakido with other techniques simultaneously. ET Madara couldn't absorb and use Susanoo at the same time.
3. Blind Madara was absorbing techniques with no eyes. You want to claim Blind Madara has Preta Path too? The fact of the matter that he could absorb while blind invalidates that he was using Gakido with Rinnegan.
4. Databook lists Nagato as sole user of Gakido.
The only similar absorption trait Nagato and Madara had was both required Rinnegan to absorb, but that trait can be said for Momoshiki as well. Everything else was different. There is no concrete proof he had Gakido, especially if he could absorb whilst blind.