modal verbs - "Would" with the perfective and progressive aspects

Consider:

A.1. The guests will have arrived last night. I could hear voices in the next room before I went to bed.

A.2. The guests would have arrived last night. I could hear voices in the next room before I went to bed.

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B.1. The lights are on. John will still be reading his paper.

B.2. The lights are on. John would still be reading his paper.

Can both A.1. and A.2. be glossed as: It is almost certain that the guests turned up last night?

Can both B.1. and B.2. be glossed as: It is almost certain that John is still reading his paper?

Any nuances between A.1. and A.2., B.1. and B.2. respectively?