Pre-emergent only works on seed that has not yet germinated. It will protect you from soon to be germinating summer weeds like crabgrass, but it will do nothing to an established plant. Which is why timing is so crucial with pre-emergent.

Creeping Charlie and the likes can be brought to heel with triclopyr.

In regards to fertilizer, what kind of grass do you have?

I actually plan to use the fertilizer in the vegetable patch. can the triclopyr be applied now?

Sure, you can apply it now. It will take 2-3 weeks to see effects.