First Sour Beer - Probably just Paranoid

I brewed a Flanders Red which is my first sour beer about a month ago

I used the Wyeast Roselare blend

Two questions -

I'm aging in a plastic bucket. I read some posts that this is OK, but others say it's too much oxygen.

I made too much wort so I fermented out 1 gallon separately. I added it back to the main batch last week but just pouring it in. Did I add to much oxygen to the mix? I know that's bad for sour beers.

Is this beer going to be lousy?

This early on, you're fine. The concern with oxygen is that it feeds acetobacter, once it gets going, which will create more acetic acid than you want... acetic acid = vinegar. Plastic buckets work, but can allow in more O2 than is desirable over a long aging period, which is something you want to be aware of. The Mad Fermentationist, I believe, prefers plastic carboys (Better Bottles, etc).