IIRC, You can either have the Maxim (and replace the Tengu with a different unit of the Striker type) or delete the Maxim and keep the Tengu, but you can't have both and have a legal Striker lance for the purposes of lance abilities.
The rules, again IIRC, say that if all units share the same recommended unit type for a lance, they gain those abilities even if they do not meet the full requirements of the lance (so six Strikers would be a legal Striker Level II even if one of the strikers falls below the speed or other requirements, if I'm reading the rules right).