If your tube amp (SE or PP) has slight hum on a 100dB speaker, that is when you put your ears close to the dustup, its perfectly fine. If its audible from a distance, in between the tracks, its a topology /design problem or components problem. (aged)
In my little experience, I have played with various tube amps and hum was not a problem. PP tube designs kind of cancel or mitigate 2nd order harmonics, where as decrease over all THD too and runs linear. SET tube amps have all the goodies of 2nd order harmonics and are generally low powered unless you are playing the exotic BIG high voltage tubes.
So far, my best experience has been running FR from tube amps, and bass active solid state fed from tube amps at speaker level input and crosses in lower mid bass region, yes both Open Baffle. Mere 1.5 watts per channel of tube power amp driver my FRs to pretty high SPL at mere 0.5-0.75 watts per channel. Its very important to have a clever choice of power / driver stage tubes and a good topology. The interstage topology with similar tubes both at power and driver stage is something very high end for some tube combos and is an expensive affair.
In case of hybrid, I don't really prefer it, if my objective is tube sound. However you can experiment to feed a Class A amp from a SE tube buffer or DHT / SE tube pre. But I would advise you not to go for a inbuilt tube hybrid amp as you lose the versatility of experimenting.
I just shared my own experiences so far and are not conclusive as I need to explore a lot further...... Many interesting things have happened and am little lazy to share here. Will do so sometime.
I have kind of resorted to either vintage or DIY stuff in tube amps. Have quite a few toys in my stable. EL84 PP, EL84 SE (sold), EL34 / 6L6 / 6V6 / KT88 / KT66 / 6F6 / 6BG6 SE, F2a SE, EL84 PPP (needs resurrection), EL34 PP williamson (needs resurrection), The 45 SE, and a new secret weapon, rare and one of its kind, takes 2A3 head-on in price and sonics......
For FRs, check new FR 12" from Beyma and another 10" FR from PRV. Beautiful drivers..... For bass duty I can suggest some as well if you wish. But these are high Qts drivers, mostly appropriate for OB or will need large boxes to sing well. OB bass can be ripole, PPSL or even H frame... Check LX521 speakers. Can be fun with smaller drivers for bass, 10" to 12" with a single, very capable FR at top, for a simple musical 2 way setup.
Vintage Sansui tube amps had great stuff under the hood. You must get the caps replaced and hum will be gone. The OPTs are special in Sansui.
Further, its a fallacy that OB setups are not good with hard rock or something similar. A well designed setup with good / sensible component support, will change your mind. It plays everything with great authority that you will not miss anything from boxed speakers.