hg38 are sourced from UCSC. Full release details (and data) are included here: http://hgdownload.soe.ucsc.edu/downloads.html#human
hg19 Canonical is the same as
hg19 except that it only includes the autosomes, the sex chromosomes, and the mitochondrial genome. Haplotype chromosomes and unknown/unmapped contigs are excluded.
For the HIV-1 genome, upload it to Galaxy and use it as a custom genome/build.
- Support FAQs https://galaxyproject.org/support/ > Preparing and using a Custom Reference Genome or Build
- Learn Galaxy https://galaxyproject.org/learn/
Hope this helps! Jen, Galaxy team