I have question, do you really need to get a an cfi, Cfii, and MII in order to get in a regional?

Not at all. Commercial Multi instrument and get your hours however you like

Do you meet ATP mins?
Do you have a 1st class medical?
Do you have a passport?
Do you have a Restricted radio license?

Most importantly, do you have a pulse?

That's all that's needed. Most people have some combination of instructor certificates because it's the easiest way to build time

Not required, it may make it easier for you to be more marketable as a CFI thus getting your experience easier. You may even learn a few things you find beneficial as you transition to the 121 world.
But in the grand scheme of things, it does very little for your regional career. You just need to meet regulatory minimums and pass your interview.

Also those ratings are boxes which you can check on major airline apps. They increase your app score, and therefore your odds of winning the lottery for an interview.

Most civilian and many military pilots have those instructor ratings, so without them you're definitely relegating yourself to the lower portion of the major applicant pool, all else being equal.

So you might need to figure out how to break out in other ways, typically that means check airman or sim instructor at a regional. CFI ratings are surprisingly not legally required for those jobs, but of course it would make you more competitive. Or you could join the national guard and get some fighter time.

I knew a guy (RJ CA) who couldn't get called. Interview consultants told him that his problem was that he didn't check enough boxes (his dad had owned a plane and he got his 1000 hours that way). Couldn't get LCA for the same reason. He ended up getting all flight and ground instructor ratings just to check some boxes.

There's a reason everybody gets instructor ratings. If you can think of something which works better, many folks here would love to hear about it!

Thanks for the answers , very helpful!!

I was going to skip the CFI route, but it just makes too much sense in getting that first aviation job and building hours. Also noticed a lot of 135 job postings specifically mention CFI and CFII as preferred. You could eventually do both, get some experience instructing and then transition to a 135 job. I think that would be nice background for moving on to the next level.