Same-Day Illustrator File Updates

I have a set of Adobe Illustrator illustrations that must be updated before the day is out. The artwork is already complete; what’s missing are several new elements that need to be layered in cleanly and on-brand... (Budget: £20 - £250 GBP, Jobs: Adobe Creative Cloud, Adobe Illustrator, Adobe Photoshop, Design, Graphic Design, Illustration, Illustrator, Photoshop)