do you think is it possible make pocketmine whith everything from MCPE (mobs, bioms, minecarts etc) without lags in this version of PHP or in PHP 7? only to know.
This question has been answered multiple times in the past, and has you may know, PocketMine is still testing a lot of features that MCPE has, for example World Generators, Entities, Inventories, Tiles, Blocks, Particles, Sounds and much more things. They all require "Data Packets" to be correctly understood. I want to invite you to surf inside PocketMine's API to understand how hard is it to understand how all these things work, and that is only "Server's Side", you may also want to make a deep research on how "MCPE's Data Packets" work for handing all its features
It would be nice as technology is advance on mobile devices and now mobile devices are much faster since pocketmine's very first release. PHP is a server side language so all the processing goes to a server, but as mcpe gets more complex, pocketmine running server starts to lag quite alot. However MiNet, a mcpe server software running on #C has considerable less lag than a pocketmine server. And it's not even stable as of pocketmine. So yes I think everything in mcpe can be implemented just that implementing more things will yield in more lag
Yes, but PHP 7 has some syntax changes (like return types...) than PHP 5. This means that the PocketMine source code needs to be converted and this may require a lot of time
Of course @shoghicp is always ahead of you guys Check this post of his... http://forums.pocketmine.net/threads/using-hhvm-to-run-pocketmine.7316/#post-80568
and why was craftbukkit a lot better then pocketmine and for far less time? or why mojang doesn´t make own server in C++ like in PC version?
Minecraft Server software was written by Mojang in Java. CraftBukkit is actually a "mod" that modifies the Minecraft Server software into an extensible API called Bukkit. PocketMine rewrites everything, from the basic network things to physics and mob AI implementation. Obviously rewriting all these require a lot more time.