You will get one Style Mod free but you have to buy Camera mod, Battery mod, etc. if you want them.
Yes, finger lock is available.
Yes, Moto Z2 Play does come with free style mod.
Yes, Moto Z2 Play 64GB comes with latest 7.1 Android OS so you may not require to update it immediately but going forward, company will produce OTA updates.
Moto Z2 Play does not have hybrid sim slot but it has dedicated 2 sim card slots and 1 memory card slot.