Is it actually needed to create a ssid for each vlan we just want to bridge from wired to wired side?
If you want your clients to be layer 2 members of that VLAN, then yes, you will need a seperate SSID / Virtual AP to be paired with each VLAN.
If some of the VLANs you're transporting on the wired links have no connection whatsoever to wireless clients, then of course you do not need to setup a wireless interface / SSID / virtual AP for them. Just define them on the wired ethernet interfaces where they're needed and that's it.
Wouldnt it be enough to have a ssid to the master interface and set encryption on this?
The master interface (wlan1 in my examples) is not special in this regard. It's just the place where you can set the physical 802.11 attributes of the link, like frequencies, power etc. Other than that, the virtual AP interfaces are basically the same.
In the configuration example i see you must do it this way by using virtual ap for each vlan. What about creating vlan wireless interfaces and bridge form eth vlans to wireless vlans (Cisco method)?
I think there is no such thing as a "vlan wireless interface". What would that be? I must admit that I've never tried something like your setup on Cisco equipment myself, but even on Cisco I don't see what a "vlan wireless interface" should be? It might be possible that Cisco can transport an 802.1q VLAN trunk transparently over a radio interface, making it work just like a wired ethernet interface in 802.1q trunk mode - don't know, but I think that's not what you're asking for and not what you're running now.
Given the fact that a normal wireless client does not know anything about VLANs and will not be able to send/receive 802.1q tagged frames over the radio, I don't see something like "vlan wireless interfaces" to be possible.
Therefore the SSID (mapped to virtual AP interface) is the only differentiator to separate multiple wireless networks.
The only other vlan we must have a ssid to is to the WISP customers.
See above. If you don't need to mix wired and wireless clients within one VLAN, then you will not need any wireless setup for that VLAN.
Maybe a dumb question but when i create vlans how can i reach the ip on the APs? Is they by default on vlan 1?
There are no special management addresses or management VLANs on RouterOS by default. You may add as many IP addresses on whichever interfaces you like, and then you'll be able to connect to you AP on that addresses (but use the RouterOS firewall!)
A word of caution: Always keep in mind that your RouterOS access point is a full-featured router. In a setup like the one we're discussing, once you begin to configure more than pure layer 2 on your AP and start to add IP addresses to more than one of your interfaces (be they bridge interfaces, VLAN interfaces or wireless interfaces) you're facing the risk to kind of "short-circuit" the VLAN separation with the routing functionality of the AP, i.e. you might create a setup where two VLANs that are supposed to be strictly seperated can talk to each other via routing!
Always be aware of that and carefully use the RouterOS firewall to prevent this if required (try using in-interface and/or out-interface in filter rules within the forward chain).