How does SelectKBest order the best features?
No, SelectKBest and other *Select* transformers from sklearn.feature_selection do not change order of features, only drop not selected ones.
Anyway, generally, machine learning models do not utilize relative order of a feature.

If you need to check and reorder features, you can use scores_ and/or pvalues_ attributes of a fitted transformer (e.g. SelectKBest) object.

Under the hood those classes use a boolean mask to identify which features to keep. The boolean mask is composed using the first (or the only) set of scores. Those would be t-values in your case. p-values are not used by SelectKBest to select features for now, according to the source code.