Sorry, that's bad use of pronouns on my part. What I was trying to get across is that the effects of gravity a star, or gas cloud, or whatever feels is mostly not due to the central black hole. The star feels forces of gravity from all the mass interior to its position in the galaxy. For example, our Sun is 8 kpc away from the central black hole, SagA*. Even though SagA* is massive, we're just so ridiculously far away that the force of gravity exerted by SagA* on the Sun is tiny. Instead, what keeps the Sun orbiting is the force of gravity applied from stars and gas closer to the Sun. So increasing the mass of the central black hole would have almost no effect on the Sun's orbit, and the same goes for most the stars in the galaxy.

Yes, for a couple reasons.The majority of mass in the galaxy does not orbit the central black hole, but orbits the all mass interior to its position in the galaxy. The strongest effects are from the stuff closest to it, as the force due to gravity decreases as a inverse square law. Adding mass to the central black hole would increase the gravitational forces felt by the stars that directly orbit the black hole, changing their orbital motion significantly, but the rest of the stars further away wouldn't feel these effects. You need some relativity spread out distribution of mass (dark matter) to explain why all the stars in the galaxy orbit faster than they "should", and not just the ones around the supermassive black hole.

Additionally, there are galaxies without supermassive black holes at their centers and we still see these "anomalies" in their orbital velocity, so you'd have to come up with some other explanation for these galaxies.

And finally, on a case by case basis, we have measurements of stellar orbits around SagA* constraining it's mass, and independent mass measurements from the event horizon telescope for SagA* and M87, so in these two cases we have even more evidence for it to not just be a bigger supermassive black hole.

Edit: Changed confusing pronouns

Just adding a couple corrections:

> which sets a lower limit of about eight times the mass of the Sun.

While this is the lower limit for how massive a star must be to undergo a core collapse supernova, the remnant left behind is not the same mass as the entire star, but closer to the mass of the iron core, as the outer layers get ejected in the supernova explosion! Successful core collapse supernovae can explode and leave behind a ~1.4 solar mass neutron star. If the explosion is asymmetric, some of the mass can remain bound to the neutron star and fall back onto it. If enough fall back accretes, the neutron star will no longer have enough pressure support to be able to resist collapse into a black hole. Otherwise, sometimes the supernova fails, leading to direct collapse. With these two routes combined, core collapse supernova potentially make black holes 2 - 100 solar masses.

> the only confirmed mechanism for the creation of the black hole is the collapse of a massive star

Additionally, I think it's safe to say core collapse is not the only confirmed mechanism of black hole formation. There are two other generally accepted black hole formation routes, although they are much less frequent: Accretion induced collapse and neutron star mergers.

In x-ray binaries, material from a non-compact star can accrete onto a neutron star and cause accretion induced collapse, much like the fall back mechanism.

Additionally, neutron star mergers can create black holes of ~2 to 4 solar masses, if the combined remnant from the two of them exceeds the maximum mass of a neutron star.

Molecular clouds are thought to be made from overdensities, or filamentary structures, in the interstellar medium where lots of atomic hydrogen is collected. We don't know precisely how these filamentary structures themselves are created, but the leading theory includes contributions from:

1. Spiral density waves (the same waves that form galactic spiral arms) and other global galactic gravitational instabilities

2. "Supershells", basically the compression of the ISM by stellar winds, supernovae, and other ionizing radiation.

3. Turbulent compression, the stochastic movement of the ISM

We don't know the relative importance of each of these processes, but that's the general idea.

[Big ol' review of Star Formation for the brave of heart] (https://arxiv.org/abs/0707.3514)

This article may interest you: It's what the Earth would look like through JWST at 40 light years away.

However, none of the planets in our solar system are particularly amenable to being detected by an instrument like JWST, see here and here. JWST is best at finding exoplanets via transit light curves, and these mostly find "Hot Jupiters" or "Warm Neptunes", planets with larger masses that are much closer to their star than any of the giants in our solar system are to the sun. JWST can also do direct imaging of planets, but that works best for planets that are very far out like Neptune, but also massive, ~10x the mass of Jupiter. So our solar system is not a very good candidate for finding anything at all with just JWST. They'd be most likely to find Jupiter through radial velocity measurements using a optical telescope with better spectral resolution, for example the Keck observatory has likely detected a Jupiter twin.