Can spatial index be a part of a multiple columns index?
No, you can't.

An index, in MySQL, will either be 


a BTREE single or multi-column index.
a HASH index (available only for MEMORY tables), that can span several columns.
a SPATIAL index (available only for MyISAM tables).
a FULLTEXT index (available for MyISAM and 5.6.4+ InnoDB tables), that can span several columns of CHAR, VARCHAR or TEXT type.


You can't combine these types.