Can sentences be grammatical if commas are added?

1. "He with the hat knows her with the scarf"

2. "He, with the hat, knows her, with the scarf"

3. I pity them who lost their money on gambling.

4. I pity them, who lost their money on gambling.

I know 1,3 are wrong, but if I add commas in 1 and 3, are 2 and 4 correct?

To me, without commas added, 1 and 3 sound wrong. I mean 1 and 3 seem to convey very awkward meanings.

In this case, I think commas must be needed because "he", "her", "them" are already definite in the context, so those parts set apart by commas are not essential information. For this reason, if commas are added, I think 2 and 4 are, at least, grammatically correct, although there's more-natural wordings than 2 and 4.

Is my thinking correct?