Bloodlines, superior ninjutsu and equipment and taijutsu styles are all entirely reasonable things for clan ninja to have (counting seals under "equipment", because even if they can't make their own, they can certainly afford to get some made by clan/village sealmasters).
I will make the comment that I've made a few times, though, which is to say that it's a mistake to project the present too far into the past. Remember the entire Village system sprang up in living memory and stabilized only after some horrendous wars. Before the village system, clans were much more mobile, guarded, and had less resources to spend on enhancement because the majority of their wealth and attention was going to the status quo. They had to live in civilian communities (because where else were they going to live, the woods?), and it's likely that many of them even concealed their ninja status a lot of the time. They didn't have big, vulnerable estates where they could work in peace and security on enhancing their ninja powers, secure in the knowledge that an entire ninja village stands between them and a sudden attack killing their entire family.
What you are seeing now, with this specific batch of clan heirs, are the first "children of peace". Children who had a chance to grow up with all the benefits of wealth and clan membership and everything starting to pull together and kick in as multipliers to their power, but without having to be marched off to war as soon as they could reliably chakra enhance themselves. Who actually have people outside their own clan they can go to for seals and equipment.
If anything, all of this is highlighting that we've been sticking too close to canon in modelling the resources and abilities of other ninja, rather than allowing them to optimise the way you optimise. The Nara have every qualification a researcher could possibly need--why wouldn't they have unique and powerful seals coming out of their ears? Likewise, the Hyūga are prodigiously wealthy. If they want superior gear for their most promising ninja, they should be able to afford it without blinking an eye.
Mainly the Nara seem to have gone in for Technique Hacking over sealing, which is how they created all their shadow jutsu in the first place. Don't forget that what they do is technically not a bloodline, just some specialized jutsu that in theory anyone could learn. (Also, just going to put this out there, but I think this characterization you have of them as an entire clan of geniuses is really
weird. There's nothing in canon implying that, and I don't know why you decided to do it for MfD.)
I can actually see why in some ways developing new jutsu techniques is superior to sealing on a clan level, even if sealing can achieve greater effects. Once a sealmaster creates a seal, he's the only one who can create it. If another sealmaster wants to duplicate it, it's an entire research project for them to be able to make that seal for themselves. Meanwhile, a new ninjutsu can be caught to a ninja in a day. And as we've seen, many ninjutsu can have useful and powerful effects even at Rank 1.