Yes they get indexed, obviously some of them get deindexed over time and some get removed. I try to reuse ones that got removed or deindexed on another parasite. I have an excel sheet i use for tracking whats going on with them.
I use speedylinks and omegaindexer, because they are automatic indexer. I totally avoid manual indexers, may be cheaper but huge huge time wasters.
Around 500+. Health niche are difficult to rank but most bang for bucks i.e. higher payouts.
Parasite rankings are always changing. Theres parasites itself, some are more powerfull some are less. Then you articles. Some willl rank higher some lower. I target 1st page.