In my individual opinion as someone who works with paint a lot (I develop the stuff in a lab and have been doing for about 6 years) you would probably get away without a mask – I probably wouldn’t wear one for that job.
Sanding it is worth having a dust mask, especially if you are using power tools. Googles may also help.
The paint itself looks like a fairly standard consumer use 1k. Nothing particularly nasty in there for the infrequent user. I’d recommend you cover your eyes in all cases. IF the van is outdoors you are not going to be in there for more than baout 4hours and the doors are all open then that will probably provide sufficient ventilation. The main inhalation nasty if you are brush/roller applying will be the solvent. A bog standard hydrocarbon, nothing aggressive.
Anywy if you do get a mask I’d go for the 3M one. They are our standard solvent masks at work and are relatively comfortable and up to the job. It looks like the other one is only a particulate mask. It mentions aqueous (water vapour) filters but not solvent so it may not protect you in this instance.
Being clean shave is essential for the mask to work properly. The beardy sprayers in our company have to wear full face air fed respirators because otherwise the air just comes round the side of the mask.
The 3m will also work for dust but it may work out cheaper to buy some of the lighter ones for that.
Covering your skin is advisable just because it is easier to prevent paint getting on you than it is to clean it up.