All pcr starts with ssDNA after the first denaturation step so I would either start a normal pcr without denaturing the first cycle or just treat it exactly like a normal pcr. Not denaturing might be preferable if your template is very long but short ss dna is more robust and just treat it as a normal pcr

Yes, it will work fine. This is what happens during all reverse transcription PCRs as the initial template (first strand cDNA) is single stranded. I would not skip the denaturation step because depending on the template, the ssDNA may form a secondary structure, which the denaturation step would melt.

It is like normal amplification with cDNA in two step RT-PCR.