Lowes lists this as mortar/fire clay? Will it be alright?

https://m.lowes.com/pd/CastleLite-50-lb-White-Type-Fire-Clay-Mortar-Mix/50214635?branch_used=true

the clay that people seem to use i think is modeling clay from art suppliers

Yes use pottery clay. Don't use mortar clay unless you want to destroy your body.

I believe this is what you're looking for:

http://www.gladdingmcbean.com/sites/default/files/attachments/74%20Mortar%20Clay,%20Lincoln%20Fireclay%20EN%20OSHA%20GHS%20SDS%202015-04-09.pdf

"Causes skin irritation. Causes serious eye irritation. May cause cancer. Causes damage to lungs through prolonged or repeated exposure."

Any finely-powdered mineral will cause cancer and lung damage. It has nothing to do with the type of clay, and everything to do with it being easily-inhaled rock dust.

if I wear a mask prior to mixing the clay, it should be pretty much harmless then?

This is a terrible idea. Use pottery clay.

As with the above advice, use pottery clay like Bentonite or Kaolin, and definitely use a particulate mask when pouring and if possible a fine water mist as well to limit dust. add water slowly while mixing, so things do not get too runny, ,and let the clay stand and saturate before use if you have the time. If it thickens too much with standing add some more water SPARINGLY!

The main ingredient in mortar clay is called Standard Portland Cement, which, according to Wikipedia, is caustic and can cause chemical burns.

Also, why are you so enamored with this particular type of clay? Why not use pottery clay?

I mean, if you want to ignore all of the warnings that everyone else has given, it's your right to do so, but it's probably not going to end well and you may lose sensation in your lower regions when the skin there burns off.

Your crazy dude why you even asking questions still after everyone has warned you of the dangers??

Thank you for advising me on the dangers of mortar clay. Thank you friends

Friend told me cement had lye in it and caused burns when it gets in you and the water dryers out so make sure u don't use anything w cement in it