LOL, sorry I assume too much, I assume the welding will be done by a professional or someone who would take into consideration liquids and fumes.

Perhaps a welder's blanket could be used to put a level of protection between items.

A fan to disperse the fumes if any may be a good idea.  

The welding involved is quick tack welding not continuous joint welding. Yeah, I know a spark is a spark but again, if a good welder knows what they are doing it should not be a problem.

A fire extinguisher on hand is always a plus when welding anything.   For that matter they are good to have at hand anytime. St.