Round 3 - I only count a total of 45 sts (5 petals of 9 sts = 45). Also ignore the previous comment about round 2 having an extra stitch at the start as this makes sense now.

Round 2 - I would say ”secondary” instead of 2ndary as it just seems more professional - this may just be me being a little bit ”nit-picky” and definitely isn‘t a required change! Same note as with round 1, I don‘t think you need to state that its creating the petals in brackets, as the subheading already suggests that. Where it says ”ch 2 st” at the end of RND 2 it suggests the ch2 acts as a stitch. I would just say ch 2 or ”the base of the ch 2” to avoid confusion/mistakes. 2a - I would try and space out the steps a bit more, maybe move them onto a new line or something as you have to read it more carefully than usual. This may become clearer later on in the pattern but the first section of round 2 would be a total of 5 dc and 1 tr, whereas all other sections are 4 dc and 1 tr (made up of the 2 incs and 1 tr across 3 sts).

Round 1 - I don‘t think you need the ”(creating the centre)” part as the subheading already shows that it is the centre section. For part 1a I would just say ”sl st to join the rnd” as it is simplified but still reminds people of how to join the rounds - this will make the pattern more beginner/advanced beginner friendly!

This, again, is a personal preference and nothing to do with the actual pattern. But I think changing the ”Use 3.5mm hook...” to a note instead of subheading will clear the layout up a bit! I would also add ”For the standard size cherry blossom coaster...(use a 3.5mm hook)” to clarify, similarly to what you have stated in the note below about the larger coaster size.

I personally think the note before step one is slightly confusing and ”wordy” - I would shorten this where possible as I had to read several times before actually understanding what was being said. E.g. ”For the 5th Cherry Blossom there are two options. Option 1 - use a larger (4 or 4.5mm) hook. See later instructions for Option 2.”

Just looking over the pattern, I would say you likely don‘t need to add all of the abbreviations as Ribblr automatically adds these for you - also, the terms will be different for UK/US but Ribblr‘s automatic abbreviations update based on language preference. I would still leave in the section about the () and [] though to clarify to readers the difference!