...but in all guidelines it is said, I need to configure one set of vlans to downstream switches, which are connected with vpc, and for orphan ports I need to configure another set of vlans, prune it from peer-link and make separate trunk link only for this vlans.
Mmmm yes and no. I mean, it is definitely not mandatory to do this. It might be suitable for specific scenarios/designs to have dedicated trunk for non-vpc vlans (vlans not configured on vPC enabled port-channels), however, vPC is quite versatile and has a lot of features which help orphan connections. So generally speaking, you can allow all vlans over the vPC peer-link without an issue. I would suggest to read the following vPC design guide: https://www.cisco.com/c/dam/en/us/td/docs/switches/datacenter/sw/design/vpc_design/vpc_best_practices_design_guide.pdf It is written for nexus 7000, but the concepts apply to all Nexus platforms, and is probably the most complete and well explained vPC guide out there.
Once you finish it (it is one afternoon of reading) I am 100% positive you will find the most suitable design for your scenario.
If not, and if some things remains unclear, please do not hesitate to come back here and ask questions :-)
Regarding your specific question (connecting switches using non-vpc), I am not sure why you would not want to connect the switches to the vPC. In the end, you have redundancy, all links are utilized (no STP blocking ports) and you do not have to worry about vpc failure scenarios. In the end you only need to configure the ports in a port-channel (even as static if LACP is not an option).
Stay safe,
Sergiu
