chevrolux: I feel like Meraki would just be a bit OTT for this situation.
The reality is there are bugger all copyright notices going around so I really wouldn't worry about it much.
I would just go Mikrotik. Set up the Hotspot and that will give you guest speed/time/quota control. Then if you really want adult filtering use OpenDNS's service but only apply it to the guest wifi network and keep a separate network for your own personal use.
A Mikrotik RB951G-2HnD is only about $120ish. Then you just just use little RB9512n as extra AP's if required. So so so much cheaper than Meraki kit!!
And if you really really want to filter torren applications etc there is the Layer 7 firewall and some other clever things in RouterOS.
OP already has a Fritz!Box for a router, so the only Meraki kit required would be an MR12. Yeah could be OTT but still a valid solution (as is the Mikrotik) - but sometimes people are after the simplicity of plugging in one device, knowing that it is going to be automatically updated, easy to use, have phone support available and a lifetime warranty if anything goes wrong
EDIT - OpenDNS, Google DNS or any other DNS filtering service unless based in NZ can break CDNs so you could end up with slower browsing and using more data which would normally be unmetered over Snap. I'd caution against using unless last resort.