Summary: VARCHAR and TEXT are identical for reading, storing, FULLTEXT, and virtually everything else. Some INDEX/SELECT differences are noted below.
MariaDB and MySQL are (I'm pretty sure) the same as each other in this area.
Some reason for 765? What CHARACTER SET are you using? (Ascii versus utf8 -- there could be differences.)
For "small" VARCHARs (up to 512?), there is a minor advantage over TEXT: When a query need to create a tmp table, small VARCHARs let it be done with MEMORY. TEXT forces MyISAM for the tmp table. This is likely to impact the speed of some queries (MEMORY is faster).
TEXT cannot have an ordinary INDEX; small VARCHARs can. (I am not sure about 765; try CREATE TABLE; it will spit at you if that is too big.)
You can use a "prefix" index, such as
INDEX (foo(55)), but it would be useless for your
LIKEs, and often useless for any other purpose.
UUIDs should be packed into BINARY(16), similar to what was mentioned for Postgres. 16 is smaller, hence more efficient.
LIKE '%foo%' works the same for VARCHAR and TEXT. Same speed, same syntax, etc. The leading wildcard makes the use of an INDEX impossible, thereby disallowing any index optimization.
FULLTEXT indexes work on VARCHAR and TEXT, in MyISAM and (as of ~5.6.4) in InnoDB. But FULLTEXT is word oriented and has a number of caveats. Furthermore the caveats are different between MyISAM and InnoDB.