during april mwinds which would bother anything would be a rare thingy, but of course such is possible to occure at any given time of the year, you can't ask for such to be guaranteed for no given time of the year, it's the weather, ridiculous to expect it to be forecasted for more than the next 24hrs ahead of time.
as fo the beaches,
Travelpro, while your statement about the Catalonia Reesort been corrct, but you should hav eincluded that the becah at the Paradisus POalma Real is the same calm and quiet and white one, no need to recommend an other when the asked for been perfectly fitting.
as for the Seaweed, you will find it throughout the year at many time in all kinda quantities at any beach throughout the caribbean, including punta cana, no menpower could control that part of mother nature.
asfor possibilities of snorkeling from the beach, they are NOT givemn at the Hotel Mainstrip/Bavaro, where one hotel is located aside an other with all swimming restricted to just the roped in swimming zones, the same applies for snorkeling, as it is prohibited to swim or snorkel outside of those areas, due the high danger due the all day long present boattraffick right outside of the ropes.
the beches with less to nothing of boattraffick where snorkeling from a beach is possible are the
Clu b Med
Punta Cana Resort & Club
Sanctuary Cap Cana
all the rst is located on roped in crowdy beaches with heavy boattraffick in front