1- u can use what glass u want- 12mm minimum- grade 1 glass gives u better clarity but up to u.
2- 2ft sump should be good-refugium optional.
3- lots of bros sell 2nd protein skimmers in pasermalam forum- depends wht brand u want but u could get one sutible for ur tank for around 100- just depends.
4- chiller yea 1/3 or 1/4 hp should be fine- but anyway ur tank is softies u u should just give fans a try- as other bro said as long as its under 29 degrees its fine for softies.if u wan chiller artica chiller brand new are pretty pricey so maybe try find 2nd or i also think haelia is not bad- just up to u and how much $$$$ u wan to spend
- lights really up to u whether ur wan led-t5-MH. think u would need 4 tubes of T5
and for wave maker u cld use the wp25- or if u wan cheaper u could go for sun sun but not controllable.
if u need any other info- pm me
cheers jack