Is it advisable to transfer all the funds from your OA to SA to earn the higher interest rate to grow our CPF funds? Are there any things that I have to be mindful of before doing so?

It is good to transfer for it to grow. But u will not be able to undo the transfer so be wary of that.

For property purchases, its also good to leave buffer in CPF OA (if you are paying the loan on cash). This helps cover the loan when you get hit by retrenchment.