He could. The Flash seems to remember everything.

Its never said that Thawne remembers the events of Flash Season 1.
What's more likely is that he learned about what would happen to him, either from Barry during the months he was imprisoned in the Flashpoint timeline, or sometime after the events of Flash 3x01.
As for how Flash Season 1 still occurredwell, I suppose its the same way Arrow Season 4 still occurred despite Damian being pulled from the timeline.
Formerly sn939

What I said? or what they did?
Either way I don't blame you, but basically no he is not the RF from S1, he's an alternative version of the RF from the night Barry's mother died.
Though events of S1 continue to be the narrative some how, and this versions existence erased his own past self's existence instead of the reverse which should of happened.ah beep it just look at the pretty monkey
aint he cute? runs away

I seriously cannot follow all that.

He shouldn't as he's a different Thawne than that one, but they made such a mess of the whole thing who knows, I mean they literally cocked it up when they had no need to when they made it so the past RF vanish when this one showed up despite this one being a mere alternative future version of that one so if anyone should have vanished it's this RF not the other one, they could have even had him knock out and steal his counterparts speed and do some mind muddling to make him think he did kill Nora and so that version still had to go through the entire S1 plot whilst this RF now just a regular remnant was free to do as he pleased.
As it stands it makes no sense, RF would have to live his life pretending to be Wells for no reason, to ensure Barry gets his powers, for no reason, and then some how manage to fake his own eradication from history just so he could do what he's doing nowthese freaking shows man have like no clue about how to do any semblance of coherent time travel story at all.
This RF may simply have slight knowledge of what his other past future self does but he wouldn't have his knowledge I don't think, I dunno my brain hurts stupid show.