I know this sounds like a simple question but if you have a single 1M (malee) attack die and two +2M attack dice in my pool, can a spend them all together for a total of 5M attack against the single target? So essentially, can you spend more than one modifier with a single attack die of the same type? My inclination is yes but I cannot find anywhere in any of the rule documents that confirm or deny this.

You sure can.

Rules Reference Guide page 8:

MODIFIER

Some dice have one or more blue sides with a plus sign (+)

before the value. Sides with a plus can only be resolved at

the same time as another die that shows the same symbol

without a plus. While resolving, the plus value is added to the

other die to create a new value.

Example: You roll a +2 Ranged symbol. You also roll a 1 Ranged symbol,

so you can resolve the +2 Ranged along with the 1 Ranged for 3 ranged

damage dealt to any one character. If you had not rolled the

1 Ranged, or had already spent it, you could not have resolved the

+2 Ranged die.

••A modifier cannot be resolved by itself.

The mistake many players make (including myself from time to time) is to add language or "infer" the intent of the rule. You cannot and must not do this. Simply read what is there and apply.