As others have indicated in comments, many of the rules you cite are wrong. The Wikipedia article is reliable.
Before & After Full Names: Albert est
After et: et une de plus
These two are correct.
Before onze: il y avait onze
This is correct, but I would generalize the rule to “no liaison before numerals”. For example “cent un” is pronounced [sɑ̃.œ̃] (no liaison). Contrast the use of un as a common noun: “les uns et les autres” (“the ones and the others”) [le.z‿œ̃.e.le.z‿otʁ].
After Singular Nouns: la maison est
This is correct. Une liaison interdite, des liaisons (-z-) autorisées.
Before oui: on a dit “oui”
Before H aspiré: en haut
That's technically correct, but a more useful way to think about these words is to consider that they do not start with a vowel sound: they start with a silent consonant (the “H aspiré”). For example the definite article is not elided: “*le oui et le non”, “le haut”. If the word doesn't start with a vowel, there's no opportunity for a liaison.
After Plural Nouns: les arbres en fleurs
Before the letter a: Je vais à Paris
These are completely wrong. In both cases, the liaison is optional. I'd do it in formal speech or in poetry, and omit it in everyday speech. There's no difference between à and au in this respect: “je vais au travail” has an optional liaison.