Monkey Style and other Crawling questions

[Murdock Mudeater]

First, any reason I'd need to be unarmored, unencumbered, or using unarmed strike to use the Monkey Style feat?

Second, while Crawling on all fours, am I considered having 4 legs for things where the number of legs matter (like carry weight)?

Third, any mechanical reason I can't employ a shield or melee weapons while prone/crawling?

[toastedamphibian]

No

No

No

[Murdock Mudeater]

Awesome, thanks.