If you wish to have a completed installation that works as designed while being as safe as is practical, all the instructions must be followed--without variation.
If the new tub is just for looks and you do not wish it to be functional, then do not connect it at all. The neighbors you wish to impress may not notice that it does not work.

First off, in a condominum you likely have no business wiring things yourself. It's ILLEGAL.

The maintenance disconnect must be visible from where you'd work on the tub (or you need to provide a locking provision). The disconnect doesn't need to have the breakers in it. You can install a "pullout" style disconnect near the spa. Once you do that, you could but the GFCI breakers in the panel and use the existing wiring (if it was otherwise a legal existing installation).

The subpanel in your picture shows #8 wiring, which for what would be legal using the wiring methods that would also be legal. I suspect that even that defeats what you're trying to accomplish.

There are special rules for spas (article 680)

Thank a lot for the info about "pullout disconnect" and locking provision - I'll investigate those futher.

Now, I do have both GC and electrician as well as permit pulled for that job - but they pretty much stuck at that diagram and insist on re-wiring with the 50 Amp circuit. And I wouldnt mind it, but we would need to dig a trench in the concrete subfloor or run it in cathedral ceiling - while at the end will wire that tub with the same #10 and #12 cables that are already there.

I can care less about the impression - that particular hot tub was choosen because its wired the way my old one was wired and its only 33" tall - and we have receiding ceiling in that room and low windows that we are trying not to obstruct with the tub. If anyone can offer me another hot tub option that would work - I am all ears (just dont want to do 30 Amp hot tub - we are a family of 5).

'less than 100 ft' can be just a few inches. If they insist on a subpanel, put it next to the main panel. Then run your 20 and 30 amp circuits from there. You would still need a disconnect for both circuits in site of the tub.

Else, skip the sub panel.

So, correct me if I am wrong - all I need are 3 GFCI breakers (one per each wire) in the main panel and than A/C type disconnect in the hot tub room - thus I would avoid installing their own sub panel and will save a grand or more while avoiding running a new 50 Amp circuit?

And that requirement for the "visible" subpanel would be fullfilled with the visible disconnect in more than 5 feet from the hot tub?

Can someone suggest a disconnect for 3 different cables to get into with one disconnect handle? And can you please explain what's "locking provision" means - google failed me on that one ))

No, as near as I can see there are only two GFCI breakers needed. You put one two pole with load neutral, and one two pole (which for some inexplicable reason has a line neutral connection displayed).

I don't think much of this manual. The installation instructions are just confuisng, silly, and in many places WRONG. It references parts of the NEC that DO NOT exist and the instructions (like the 5' rule for the disconnecdt) DO NOT APPLY to residential installations but the maintenance disconnect does and they don't mention the latter.

I see in the manual they PROVIDE the subpanel with the spa. They don't mandate you use it however, if you've got the appropriate wiring and GFCI's to do it otherwise.

'locking provision' means that you can lock the cover (with a pad lock or some such) or lock the breakers off (in the same way).