According to this, yes, that's the plan: https://zcoin.io/zcoin-moving-beyond-trusted-setup-in-zerocoin/
Arbitrary inflation, if you mean invisible arbitrary inflation, is impossible in Zcoin. That's one of the major advantages compared to Zcash.

And in addition to what zcoinofficial said, I think the multiple POW algo switches had a noticeable impact on the coin emission graph, as each time the difficulty had to be adjusted from zero.

And yeah, Zcash is basically missing another half a month worth of coins because they started out like this: