I have to configure a public hotspot for a very small town (with severals APs)... for wireless setup i have selected ubiquity systems... for network management i am looking for options... and after some research... the options are:

1º. Mikrotik
2º. Pfsense
3º. Zero-shell

I have several questions... as a free public hotspot we need to add some limitations:

1º. Captive portal to show conditions of use... and login page...i know mikrotik can do this...
2º. I want to cut all protocols except: pop, smtp, https, http, and imap
3º. Session limit time: 90 mins, after this time, user must login again.
4º. Bandwith limit time: each user must have limited to 500 Kb download / 300 Kb upload
5º. One common user... with several limitations... all with have the same public name (so, one user... multiple sessions), the limit must be applied to the session not to the user (that is...if there is 15 users with the same name... each of them must have 500 kb bandwith...not 500 kb for all of them).
6º. I think we doesnt need the use of user manager... (with the basic user manager of hotspot is enough...) is ok?
7º. If we use user manager... what license we need? (i know: for more than 10 users type 6... but if all users have the same name... can we have 40 sessions with the same user name with License type 4 or 5???

Thanks all and sorry for my english...

All of that is trivially possible with RouterOS. You do not need User Manager. A level 4 license can do 200 active Hotspot users, level 5 can do 500, level 6 can do unlimited.

If the 40 user sessions from your last question is the number you're actually expecting I'd recommend an RB450G. Plenty of power for that use case, not expensive, and it has a serial port which is good to have on any production gear.