ANYONE CAN GIVE ME AN IDEA ABOUT THIS?

Hello Ladies and Gentlemen.
I was looking at The all new Maxis Family Plan RM 299
4 Mobile line with Unlimited Data, Call and Sms. + 30mbps Maxis Home Fibre

Currently im having Maxis Postpaid 98 + 1 Supp line RM48 + 30mbps Maxis Home Fibre + Maxis Home 4G Wifi. ( Both line have unlimited data, call and sms)
RM98+RM48+RM89+RM108 = RM 343

May i know If i go for the new plan Maxis Family Plan RM 299.
Can it be like i use 2 mobile lines for phone and maxis fibre as now.
The EXTRA 2 mobile line that with unlimited data and call and sms,
1 i use it in my 4G router to sub my Maxis Home 4G wifi (which cost my 108 per month)
another 1 i use it in my portable broadband.

Am i allow/possible to use it like that?
Is it work in this way?
Will i get speed cap? or anything negative?

i traced back my usage.

My Principal line 98 use around 70GB per month.
Supp line 48 use around 30GB per month.
4G Home Wifi use around 300 GB per month. (mainly consumed on TV box, Video Streaming, Netflix, Gaming, Download game and etc.)
Maxis Fibre - Unknown.

With my current plan, i didnt get speed throttled.

I heard alot of people tell me about what u mentioned. But did it really go in that way? Because i used to ask the Maxis person before they say dont have such things.
Anyone really experience speed throttle before?