Is it possible to do the entire DNA sequencing with Microarray or would you have to use Sanger or NGS methods for that?
Microarrays generally capture gene products, such as mRNA (via cDNA), which have been extensively processed. Because of this, you lose genetic information such as introns or regulatory elements. In fact, what you'd end up with is the transcriptome of the organism, and it would be impossible to sequence the DNA from this. NGS methods are superior for this, still, and there is a good overview of the advantages of RNAseq over microarray here, for example. To sequence the DNA you will probably use NGS.