is it right?

I don't believe i've ever heard a native speaker dispense with the "th=" sound at the beginning of either then or than. I've certainly never done so.

No, me neither.

'em is OK, for "them".

"Hundreds of 'em". etc....

Stop speaking fast, it's doing no good.

Yes you can 98: Contrary to assertions above, Eg, "Other'n that" is very common collo

And that Dale is piss-poor English. Sure, you can say it that way but it will reflect pretty poorly on the speaker and his or her seemingly lack of proper education.

It only works as colloquial marketing text in a informal advertisement.

My Golly Tsar, thanks but what rigidity! Now, 98 was asking whether or not he might (in everyday conversation I'd suppose) use this contraction. I can only guess that in my 82 years I've heard the expression many score of times, and of course I associate with only the most refined of other humanoids

I'll concede in your favor however, that when I inquired of my Better Half, who is much smarter than I, she responded "not often, maybe 10 times"

But here's an interesting aside of pertinence (to maybe me only): It usually comes out as "otherth'n" typically in "otherth'n 'at" Because the "th" is so muted, 98's rendition seems entirely reasonable