Don't wash things like PUL or elastic on 90, so you'll have to go with 50.
It will probably invalidate your warranties on nappies if you wash in dishwasher tablets, but so will washing in Persil, Daz, Bold, Fairy... pretty much any 'normal' detergent. Enzymes aren't evil - you should be able to wash nappies in biological detergent - most countries don't even have non-bio. Same with optical brighteners. Things like that do add to wear and tear, but so does washing in anything above 30 degrees, or spinning them on fast, or tumble drying. It's about risk and benefit and only you can judge that. For me, removing detergent build up is important, since not only does it trap bacteria and affect absorbency, bacteria trapped in elastic 'eats' it and can make the elastic go slack.
The only manufacturer I have seen say anything about dishwasher tablets is Tots Bots, who say they wouldn't do it because they wouldn't want something on their skin that had been washed in them. I think that's a ridiculous bit of logic, since we LICK things that have been washed in the dishwasher
Last time I checked, they didn't say it would affect the nappies, just the skin thing. I haven't checked manufacturer's websites recently though, so you might want to have a look yourself. Most places do caution against vinegar, boiling, washing soda, natural soap, borax etc though, so if they don't include dishwasher tablets I think they'd be okay, since it's a fairly widely used method now.
Anyway, if you think you may have build up, I wouldn't use the dishwasher tablet method anyway. It's the least thorough of the methods, better if you think they might be heading towards a problem, but if you have an existing problem it's probably not enough.
And yes, everything gets stripped. I normally find synthetics get build up worst - fleece is quick to get stinky - so definitely include fleece liners.