It is much easier to learn a proper technique to get out of mount in the first place and adapting it to MMA environment afterwards. One shouldn't learn things doing it in half-measures.
It seems you have not yet understood the main premises of BJJ, which hold in MMA as well:
1. Position before submission
When you are in a weak position - like being mounted - you have to fear that you are subject to ground and pound, yes. But it is not the ground and pound which should be your main concern, it should be your weak position. It does not matter what you do or what your opponent does. As long as you stay in that position, it is much easier for your opponent both to hurt and to capitalize from mistakes than it is for you. That is why your main concern is and has to be getting out of that position.
2. No compromises - effective technique or nothing
One may well think about a thousand possibilities and try to embrace and secure oneself against all possible kinds of attacks, but truth be told: you can't. Think about knife defense as an analogous example: Yes, you could think about a gazillion ways of effectively warding off the weapon and disarming the aggressor, truth be told, that is not your main goal: that is surviving. And the best way to ensure survival is disabling the aggressor as fast as possible. Yes, you try to block, sure. You prevent and mitigate as much damage as possible. But you will be cut or stabbed anyway and you will survive most of it for long enough to get help, but if you don't stop the attack, you will accumulate wounds until they become lethal. Therefore, you accept that you will get hurt because you are in a bad situation and carry on with getting out of it. It may sound paradoxical, but attack is your main focus here.
The same is true for mount: Yes, they will try to beat the sh*t out of you and you will not be able to fend off all of these attacks anyway even though you certainly try to roll punches and block them as much as possible. Therefore, the sensible thing to do is to use the most effective way to end this problematic situation with all your focus and strength, and as fast as possible. The most effective way to do so is what you learn in BJJ (and wrestling, and Judo, and Sambo, ...because it works). Starting to learn the technique, it will take you what feels like ages and you will not be able to manage strikes at the same time, but with experience and body development, you will see that it becomes much faster. Even if you get hit a few times, it will still be less damage than what you have to expect if you just defend or try other (less decisive and effective) ways to get the hell out of there.
3. On the reality of fights
Disadvantageous positions like the ones you describe do not come out of thin air: they are a consequence of you having made a mistake, being outplayed, or generally inferior. You probably already took a hit at that moment and are dizzy. All that can possibly be of help now are automatic response patterns like rolling the punches and escape techniques.
Having said this, you oversaw a major point here: Once the balance of your opponent is compromised, they cannot possibly do any effective ground and pound. Even if they hit you, it won't hurt that much, since they cannot generate power. And one of the first steps of any defense/escape will be compromising the balance of your opponent.
This holds true for probably any problematic aspect you made out. In every other one, either adding a guard is no problem, or your opponent is in a compromised position from which there are no powerful blows possible and they would risk counters which bring them in peril themselves.
It is helpful to train the situations and techniques with strikes allowed as soon as you gained some proficiency in applying them. That's what your MMA sparring sessions are for. This includes how to roll punches and protect your head as much as possible while escaping the position with the best possible technique. But without a clear plan to get out of that inferior position in the first place, you will continue to be in a disadvantageous position. And the longer this happens, the lower your chances.
Not focusing on learning the proper technique for this first but trying to learn everything at once means that it takes you longer to become proficient as a complete fighter compared to problem-specific drills.