How to use lemmas and proofs from another paper?

Suppose that paper A has two lemmas called Lemma A.1 and Lemma A.2, along with their proofs.

I want to make use of them for another paper, say, paper B. However, in the scope of my paper, I have to change them slightly, but without losing the general idea.

For instance:

Lemma A.1: The intersection of two straight lines define exactly one point.

Lemma A.2: Two straight lines can be either parallel or intersecting if they are not the same.

Suppose that I write the lemmas for planes:

Lemma B.1: The intersection of two planes define exactly one straight line.

Lemma B.2: Two planes can be either intersecting or parallel if they are not the same.

Also, the proofs for both papers are very similar. Therefore, I have two questions:

1. Can I use the same methodology with similar words to prove my own lemmas?


2. If I can, is citing paper A in my lemma confusing? If I cannot, can I just specify the lemma in paper A and say that this lemma and proof can also be used etc.?