What MySQL version do you want to map to? MySQL >= 5.03's got some changes in that department.
MySQL Varchars can be up to 65532 bytes in length (so watch out for character sets that take more than one byte per character).
MySQL DECIMAL(P,D) and MySQL NUMERIC(P,D) are synonyms, and are now stored in binary format (not string as before). It now supports a precision (P) ranging from 1 to 64; it supports a maximum of 30 decimal digits (D). BTW, I'd use some INT variant when you dont plan on using the decimal digits.
I don't know what the requirments are for your Oracle REALs and DOUBLE's, but is seems to me that you could use MySQL FLOAT or DOUBLE in some cases.
Oracle BLOBS would map to MySQL LONGBLOB, and NCLOB would map to LONGTEXT
RAW and LONGRAW up to 65532 bytes could be mapped to VARBINARY(L)
see:
http://dev.mysql.com/doc/mysql/en/column-types.html
and:
http://dev.mysql.com/doc/mysql/en/precision-math-decimal-changes.html