Audio Interface system setup

Just joined this party! A general question here. I have ordered a new PC, Spec below...

• HP Z440 WORKSTATION PC [E5-1650v4 3.60GHZ 64GB RAM 240GB SSD 2TB QUADRO K1200
• 8x High Speed USB 3.0 Ports + 2x USB Ports
• Mid-Range Professional 3D 4GB GDDR5 PCI-E nVidia Quadro K1200 with 4x Mini DisplayPorts

The PC will be used to do some Audio File engineering and also to record my Son's Guitar playing and Vocals. I am looking at some of the cheaper end of the Audi Interface bundles but have been advised to steer clear of the very cheap Behringer devices (comments on this welcome).
Sound engineering is new to me and I would like some advice on setting up this new PC and thoughts on the correct budget friendly Interface bundles that some people may have bought. I have used Audacity and have come across a few limitations, but all-in-all it is capable of doing what I need it to do, but I would like to understand how to use and what should I use to get the **required results**.
**Required Results**:

• MultiTrack Engineering: I am part of a group of people who own the original Multi Track Master Tapes (Analogue) of a well-known artist from 60's and 70's. These have been transferred to MultiTrack 96K Wav Stems and I need to be able to provide sections of these Multi-Tracks to a Record Company for release.
• My Son is playing Guitar at Grade 7 RGT level and wants to invite (Lockdown permitting) member(s) of his band over to rehearse. He also needs to record his playing for his Grade 7 examination.

So I just would like to see some pitfalls that there may be ahead of me with this and get some advice on the software / hardware I should be looking for and some ideas on how to use them.

Thank you