So I've progressively added changes to the raid solo guide (Alakazam specifically since it is a hard solo) to give more concrete recommendations that should clearly answer whether or not your team is ready.
First, the guide strongly discourages use of Pokemon that are not specifically listed counters (Using any Pokemon not one of the counters listed below is ill-advised). So disregard Gyarados, Sneasel, and Umbreon completely. You shouldn't even be thinking about them. SE Tyranitar is also not listed as a viable moveset, so that is also out of the running.
Second, the guide specifically suggests level ranges at which counters become viable. So that L30 Scizor isn't going to cut it, either.
Your Mewtwo is going to have to carry your team. You'll probably be fine as long as Mewtwo maximizes its damage output.