1. Mana Reflection doubles mana. This is not a triggered ability given the word "instead"
2. Selesnya Taps for 4 mana (due to mana reflection's static ability)
3. Mirari's Wake's ability triggers and is put on the stack
If Mirari's Wake resolves appropriately then your mana totals 5.
One correction, Mirari's Wake does not get put on the stack. Mirari's wake's triggered ability triggers off of a mana ability, doesn't target and adds mana to the players mana pool so it too is a mana ability and adds mana to that players pool without using the stack.
GRWUB Scion of the Ur-Dragon BUWRG
RWU Numot, the Devastator UWR
BUG The Mimeoplasm GUB
BUR Nicol Bolas RUB
WB Lifegain/drain BW
GB Landfall BG
RR RDW RR
You are correct.
1. Mana Reflection doubles mana. This is not a triggered ability given the word "instead"
2. Selesnya Taps for 4 mana (due to mana reflection's static ability)
3. Mirari's Wake's ability triggers and is put on the stack
If Mirari's Wake resolves appropriately then your mana totals 5.
One correction, Mirari's Wake does not get put on the stack. Mirari's wake's triggered ability triggers off of a mana ability, doesn't target and adds mana to the players mana pool so it too is a mana ability and adds mana to that players pool without using the stack.
GRWUB Scion of the Ur-Dragon BUWRG
RWU Numot, the Devastator UWR
BUG The Mimeoplasm GUB
BUR Nicol Bolas RUB
WB Lifegain/drain BW
GB Landfall BG
RR RDW RR