I don't think pearl shrimp would be happy in my tank, unfortunately. I have a gravel substrate, and as I recall, pearls like to burrow. Though please do correct me if I'm wrong.
The red claw interested me, mainly because I've read about them being safe to keep with some caridina species. I keep m. lanchesteri alongside my amanos at the moment. Thus far the only aggression I've seen from them has been towards other lanchesteri. Just investigating others that might be alright with them.
Yep, they do burrow. Sorry I can't help you further as I've never kept a red claw, but I'm sure someone else will as it does seem to be one of the more commonly kept longarms. It does go under a number of different scientific names however, so you might not find all the information on it if you searched for only "Macrobrachium Assamensis"